What is Pain?

(I would like to highlight this is about pain education, and not clinical relevance or identifying tissue damage – if you are injured please go see a professional!) 

Pain & Health

I’ve been wanting to write about pain and health for some time now, but I couldn’t find a good way to approach it. I hope that this article, which is around 3000 words in length.

I have a friend who is a pilates instructor. Before she was a pilates instructor she was a dancer. She asked me to help her out with some ankle pain she couldn’t seem to get rid of. We met, had a chat and I tried to check if anything was structurally wrong. We couldn’t really reproduce her ankle pain, and she wasn’t experiencing any decrease in function. She was just experiencing occasional pain, and had been feeling it for almost a year. I was about to talk about chronic pain, models of health and understanding modern pain science with her but she said:

‘Maybe I’m just so well aligned that when my body gets even slightly out of alignment, I notice it. I think that I just need to keep focussing on that. I’m happy that there’s nothing serious though!’

I didn’t really know what to say after that. I thought back to people I knew, and worked with and their chronic pain issues. Nearly all of them were trying to work on fixing structures or alignment. They were attempting to heal asymmetries using functional movements or core exercises. Back pain, neck pain, shoulder pain – some had been suffering for many years. Everything was about fixing alignment, improving posture and muscle balance. No-one was looking the big picture.


Models, usefulness & pain

“Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful.” – George E. P. Box.

This is an important quote. When we talk about the body in terms of systems, or metaphors. It’s not going to be ‘Truth’. It will be a model to work with. There are different ways of treating an illness or injury. Lets give a simple example of a disc herniation in the lumbar spine, and you have been suffering for 6 months with back pain: Often (depending where you are located in the world, and perceived best practices) you may be offered some combination of  pain killers, spinal surgery and/or physiotherapy. There is a logic behind the choices of treatment, based on what is believed to be causing your pain. That logic, is based on a model of cause and effect. What is causing you to feel pain, and the best way to either stop the pain, or fix the underlying problem. Unfortunately, it might not be that simple.

You are a gestalt of your systems, practices and processes. Of your mind and body. Or Body, Mind & Soul. Or just your body. Or whatever conceptual framework you wish to work with, because that’s how we describe complex phenomena. It’s too much to understand this interconnected, intertwined, biosphere we live in, and our place in it, without using models and concepts. The models and concepts we use won’t necessarily be accurate, in the same way a flawless sculpture of a person might bear a near-indistinguishable likeness to someone, but it won’t be the same as them. It will be a model of them. There are many more things affecting our experiences and interpretations than can be succinctly explained. There are models and metaphors that might help though (more on this later).  In healthcare, as in other fields, there are competing ‘models’ sometimes that people will disagree with about the accuracy or validity of.

The question to ask yourself is ‘Is this model useful?’

In the case of fruitlessly chasing better ‘biomechanics, structure & posture’ for months or even years – I’d suggest there are better models of health to work with.

The biopsychosocial model

When we look at our body in terms of health & pain and we only see us as machines, we are missing lots of things about ourselves. It is easy to fall into mistake of believing that pain = damage to the body, and therefore pain = something that needs fixing in the body. In many cases, that might have truth to it, but it is only a part of the problem. Like looking into a room through the keyhole and believing that what you see, is all there is inside. We can be less wrong in how we look at things, we can be more useful.

One such model I believe to be ‘less wrong’ is the biopsychosocial model of health.

“The biopsychosocial model is both a philosophy of clinical care and a practical clinical guide. Philosophically, it is a way of understanding how suffering, disease, and illness are affected by multiple levels of organization, from the societal to the molecular. At the practical level, it is a way of understanding the patient’s subjective experience as an essential contributor to accurate diagnosis, health outcomes, and humane care.” (Borrell-Carrió et al., 2004)




Where all three circles interact, the sum of each of the three factors, could be called ‘biopsychosocial health’ or ‘current wellbeing’. We’ll come back to this later, after talking about pain.

Pain (a very simple primer)

Quick anatomy of the nervous system, before we get going. Don’t worry too much about this!

You can separate the nervous system into three parts:

Central Nervous System (CNS) – This is your brain and spinal cord. Your thinking, and higher processing occurs here.

Peripheral Nervous System (PNS) – These are the nerves that flow from your spinal cord and brain out into the body. They send and receive signals to and from your CNS.

Autonomic Nervous System (ANS) – This is the unconscious control of things like heartbeat, gland secretion, breathing rate, digestion, urination, fight-or-flight response… all the things you don’t really thing about. The ANS can be separated into two (or three) parts:

Sympathetic Nervous System (SNS) – This is your stress response. Your ‘fight-or-flight’ response. It prepares us for threats: Increases heart rate and force of heart contraction; increases blood supply to muscles, increases sweating, inhibits digestions and constricts gastrointestinal organs.

Parasympathetic Nervous System (PSNS) – Roughly speaking the PSNS is responsible for ‘rest and digest’ or ‘feed and breed’; sexual arousal, salivation, lacrimation (tears), urination, digestion and deification. It slows the heart and guides the body into relaxation.

Enteric Nervous System (ENS) (Debated) – This is the nervous system in and around you gut and digestive system. Often referred to as ‘The second brain’.

What is pain?

Pain is not really a ‘sense’ from the body that you feel. Our bodies have receptors called nociceptors which are sensitive to either mechanical pressure/distortion, temperature change or chemicals. These nociceptors report ‘noxious’ findings, and the brain uses that information plus other signals/information to generate your pain experience.

We can separate pain into 2 main types: Acute & Chronic

Acute pain is a response to specific injury or disease. Described as generally being pain lasting less that 3 months. After three about months there is (usually) a slow change in the processes that produce pain. This is then classes as chronic pain, and it is a little bit different.

Why is chronic pain different?

Chronic pain is different because our amazing, adaptive nervous system now has the ability to generate pain even when there is no damage to trigger the nociceptors. We may 100% feel that there is something wrong with our body but there is a chance that several things have changed to make it different from acute pain: The sensitivity of the nociceptors has changed, and signals they send are being modified en route. Furthermore that signal is modified, modulated and interpreted in the brain based on other signals, thoughts and memory.

So how does out sensation of pain get generated?

Lets go imagine a twisted ankle. First, the ankle moves in an awkward manner, putting immense strain on your ligaments and muscles. The nociceptors in your ankle send a ‘noxious stimulus’ message to your spinal cord. There is a synapse there ( where nerves meet and communicate) and various signals describing what has occurred to your ankle can be transmitted up your spinal cord into your brain. Once the signal is in the brain, your brain asks your various thoughts, memories beliefs how it should respond. And  the experience that follows is your  pain experience. It happens so quickly, all you feel is ‘ouch’. Here is a equation to see factors that can affect pain:

Signal from Body + Mood + Context + Mindset + Structure/Chemical = Pain + Adaptation + Stress Response

Now, lets look a bit closer at some factors for pain. And why in chronic pain, different parts of the equation might be more responsible.


If you are in a positive, supportive place emotionally it can dampen the pain (The Periaqueductal gray (PAG) strongly modulates pain in this manner). Depression or anxiety (fear) can amplify the pain. Injure yourself on a good day or when doing something you enjoy, the pain might be modified to be lower. If you’re having a bad day or doing something you dislike, it might be amplified.


Value placed on things can change the perceived ‘threat level’ of an injury. It can make it scarier. It threatens us or means of providing a living. (A pianist would likely place greater value on their hands than a singer).

Your belief about pain and what is painful might either decrease or amplify the sensation. You might know from childhood how painful being burnt on the stove is, and that ‘pain memory’ can amplify any future burn sensations. Also known as ‘how bad was it last time?’ memories.

Expectation of the pain, such as seeing (or believing) that something is going to hurt you. Like a child watching a doctor inject them with a needle, it hurts more if they see it happen!

Placebo/Nocebo. If you have taken medication, received acupuncture or massage that might dramatically affect your pain, even if on a biological level it does nothing.

Survival value. A broken arm having fallen in your living room would be very painful, and not an enormous threat to your survival. A broken arm in a war-zone, when bullets are flying overhead might not hurt until after you have reached safety – there are many similar stories from war.


If you are in a hyper-vigilant frame of mind, or particularly distracted this can amplify or decrease the pain sensation.

If you are worrying or catastrophising about it, it would serve to increase the sensation. If you are inclined to be stereotypically macho, that might decrease your pain experience.


The nervous system is incredibly adaptable. It is changing all the time. It is constantly adapting to the signals is receives. Every time you practice yoga, your nervous system gets better at doing it.  You motor cortex adapts and learns the movement better (which is why practising is important). Or perhaps when you are stretching certain parts of your body, your somatosensory cortex develops a larger image of the area you are focussing on, improving it’s awareness of the area. Your nervous system get better at what it does, and this adaptation is great. It can, however, adapt to things you don’t want it to.

Chemically, it can be influenced by painkillers that dampen our sensation either in the CNS, on the PNS.

Which brings up on to the other side of the equation:


We can call this your ‘pain experience’. Pain can have different qualities and components: Location/Site; Intensity; Duration & Quality (Burning, aching, shooting, stabbing, shallow, deep, specific, vague etc)

Clinically this information is relevant as certain ‘qualities’ of pain can be linked to certain tissue types and injuries. (Shooting, linear ‘electric’ pain often indicates nerve pain, for example).

This is your ‘ouch’ sensation.


These are the ways in which you adapt, both consciously and unconsciously. Short term and long term.

Thought Pattern Changes: These are things like avoidance tactics, habits, mood or mindset changes. As we have seen above, these things strongly affect our pain. We can become more antisocial to avoid having to go out, due to the pain. We might stop certain hobbies or exercises because they become too hard. We could start a habit of taking strong painkillers to manage the pain.

PNS Changes: Hyperalgesia is when your nociceptors are extra sensitive, so that what was previously a small signal becomes a big signal. Allodynia is where things are so super sensitive, that what previously wouldn’t have registered as pain, now does (Think of how sensitive your skin get around a cut, burn or bruising: light touch = pain). Sometimes these can persist into chronic pain.

These are specific examples of peripheral sensitisation. Where the peripheral nervous system, becomes highly sensitive and sends more messages, for less and less stimulation.

CNS Changes: There is a part of the brain called the somatosensory cortex, this is where you brain has an image of your whole body. That image’s size, relates to it’s awareness and sensitivity of an area. Hands, fingers, tongue, genitals, lips… all are huge in the somatosensory cortex. If you are a pianist, for example, your hands and fingers would be extra large. If you have been suffering chronic pain, however, that location would become much larger too (and much more sensitive to your brain). It might also become more ‘blurred’, less precise. So controlling in becomes harder. Feeling very specific sensations becomes harder, more vague.

If you repeatedly get nociceptive signals from your body, and you don’t ‘deal’ with them well (they are amplified and worsened by mood + context + mindset) then your nervous system may adapt to become more sensitive and more protective of the area.

Your somatosensory cortex, which once had a lovely clear image of the region you injured, now has a fuzzy image of it. It has grown larger too, to you are more aware of it, but less accurate in your awareness. Your motor cortex may have developed a ‘pain memory’ of the injury. So now moving your body in a similar manner to how your pain occurred can trigger pain.

And, much like with the PNS, these can be problems of Central Sensitisation. Where your CNS becomes highly sensitive and generates a greater ‘pain’ signal, from the available information. In some extreme cases, people have been able to generate redness, swelling and pain just by thinking about it.

Stress Response

The stress response is a response to a stressor or environment. In humans it is activated by the sympathetic nervous system and/or the Hypothalamic–pituitary–adrenal axis (HPA axis) (The HPA axis works hormonally)

The sympathetic nervous system, along with the HPA Axis, when facing a perceived threat can go into overdrive. Which is fine in the short term, but in the long term it can have negative impact on many factors. (I urge you to read Robert Sapolsky’s ‘Why Zebra’s Don’t Get Ulcers’ if you haven’t already).

Well, when you are experiencing ‘stress’, you body can’t differentiate between a physical stress and psychological one. Being chased by a lion might generate almost the exact same response in the body as giving a presentation in a room full of people. The stress response diverts energy to where it would be needed if you had to deal with a hungry lion. It diverts blood away from parts of the brain, digestive system and reproductive system: meaning potential problems testosterone levels, erectile dysfunction, menstruation, menopause, irritable bowel syndrome(IBS)/digestion and short-term memory/concentration. It pumps extra sugars into the blood in case muscles need them, meaning that it can create problems like type-2 diabetes. It increases resting muscle tone, meaning your body is more tense. This can generate more muscle aches and pain. It

Long term or chronic stress can have symptoms such as anxiety, depression, social isolation, headache, abdominal pain, lack of sleep, back pain, poor concentration, panic attacks. There can be an increased risk of heart disease. It also suppresses the immune system, meaning higher risk of disease and infection.

 Putting it back together:

Returning to the biopsychosocial model, we can see that the factors that have an effect of health/wellbeing are very similar to the factors that have and effect on pain experience.


And, as we learnt before, many of the adaptation and stress response can have a huge effect on these factors! It’s a feedback loop.

Signal from Body + (Mood + Context + Mindset + Structure/Chemical) = Pain + Adaptation + Stress Response

When we really think about the equation, it might be written like this:

Signal from Body + Biopsychosocial Health = Pain + Adaptation + Stress Response


Feedback loop

The factors that influence and effect our biopsychosocial health help us modulate, modify and interpret (for the better or the worse) our pain. Conversely, the way we experience pain and it’s effect on us can impact our biopsychosocial health, creating a negative feedback loop which means we are sometimes in a situation where we can’t escape our pain.

Because this ‘feedback’ loop, is what happens in chronic pain. It feeds back into the system and re-amplifies it.

So, what can we do about it?

The easiest thing to do is to look at ways of managing your biopsychosocial health and your stress response.

There are many different approaches. My approach is based on OsteoMAP (Osteopathy, Mindfulness & Acceptance) combined with Stretch Therapy (Promoting Grace & Ease in the body). I call it ‘StretchMAP’. I Will write a separate article of that approach at a later date.

The most important things to realise is that:

1) Pain doesn’t necessarily mean damage.

2) Chronic pain might best be treated by addressing your thoughts, feelings and actions.

3) Stress might best be treated by addressing your thoughts, feelings and actions too.

4) And that including approaches such as: Mindfulness, Cognitive Behavioural Therapy (CBT), Stretch Therapy , Pain Education or Stress Education can be incredibly potent tools.

Suggested reading, if you are interested, would be:

– Explain Pain by David Butler and Lorimer Moseley

– Why Zebras Don’t Get Ulcers by Robert M. Sapolsky

References / Bibliography:

Ali, N. and Thomson, D.I. 2009. A comparison of the knowledge of chronic pain and its management between final year physiotherapy and medical students. European Journal of Pain. 13(1),pp.38–50.

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Borrell-Carrió, F., Suchman, A.L. and Epstein, R.M. 2004. The Biopsychosocial Model 25 Years Later: Principles, Practice, and Scientific Inquiry. The Annals of Family Medicine. 2(6),pp.576–582.

Butler, D. 2013. Explain Pain 2nd edition. Adelaide: NOI Group.

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