Healthcare Professionals
Pain Science & Chronic Pain
Modern pain science has changed how we understand chronic pain. Pain isn't simply a direct measure of tissue damage.
A contemporary understanding of pain recognizes the interaction of biological, psychological, and social factors, while also recognizing that different pain mechanisms can coexist in the same person.
Pain is real. But pain isn't a direct measurement of tissue damage.
Pain is a personal sensory and emotional experience. The International Association for the Study of Pain emphasizes that pain and nociception are different phenomena and that pain can't be inferred solely from activity in sensory neurons.
This distinction is important because it helps explain why pain can sometimes persist after an injury has healed, why pain severity doesn't always match imaging findings, and why effective chronic pain care may need to address more than tissue pathology alone.
WHAT IS PAIN?
Pain Is an Experience, Not Simply a Signal
Pain is defined by IASP as an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.
Importantly, IASP's definition also notes that pain is always a personal experience influenced to varying degrees by biological, psychological, and social factors.
This doesn't make pain imaginary or “psychological.” It recognizes the complexity of how the nervous system, body, mind, environment, past experiences, expectations, and context can interact to shape the experience of pain.
PAIN IS NOT THE SAME AS NOCICEPTION
Nociception is the neural process of encoding noxious stimuli. Pain is the resulting personal experience. The two are related, but they aren't the same thing.
Nociceptors detect potentially threatening stimuli and send information through the nervous system. The brain then integrates that information with many other sources of information before producing a conscious experience.
This is one reason why the same physical stimulus can produce very different pain experiences in different people — and why the same person can experience different levels of pain under different circumstances.
THREE IMPORTANT PAIN MECHANISMS
Nociceptive Pain
Pain arising from actual or threatened damage to non-neural tissue involving activation of nociceptors.
Examples can include pain associated with tissue inflammation or injury.
Neuropathic Pain
Pain caused by a lesion or disease of the somatosensory nervous system.
Examples can include certain forms of nerve pain associated with nerve injury or disease.
Nociplastic Pain
Pain arising from altered nociception without clear evidence of actual or threatened tissue damage causing nociceptor activation or a lesion of the somatosensory system causing the pain.
Nociplastic mechanisms can occur alone or alongside other pain mechanisms.
AN IMPORTANT CLINICAL POINT
Pain Mechanisms Can Coexist
Chronic pain shouldn't always be placed into a single category. A person may have more than one pain mechanism contributing to their experience. This is sometimes described as mixed pain.
- Tissue injury and inflammation may contribute nociceptive pain.
- Nerve injury or disease may contribute neuropathic pain.
- Altered nociceptive processing may contribute nociplastic pain.
- More than one mechanism may be present at the same time, creating a mixed pain presentation.
Recognizing that pain mechanisms can coexist can help avoid oversimplifying a person's pain into a single label or assuming that one treatment approach will address every contributor.
NEUROPLASTICITY AND CHRONIC PAIN
The Nervous System Can Change
Neuroplasticity refers broadly to the nervous system's ability to change its structure and function in response to experience.
In chronic pain, changes in sensory processing and pain modulation can contribute to increased sensitivity and persistence of pain. These changes are part of the reason chronic pain can continue even when the original injury or disease has changed.
Neuroplasticity shouldn't be presented as proof that all chronic pain is caused by the brain or that pain can simply be “reprogrammed.” It's one part of a much larger biological, psychological, and social picture.
HURT DOESN'T ALWAYS MEAN HARM
Pain can be a valuable warning signal, but the presence or intensity of pain doesn't always indicate the amount of tissue damage occurring at that moment. Likewise, a structural finding on a scan doesn't automatically predict how much pain a person will experience.
PERCEPTION, CONTEXT, AND THE PAIN EXPERIENCE
The Brain Does More Than Receive Signals
The nervous system continuously evaluates incoming sensory information alongside previous experiences, expectations, attention, emotions, and the surrounding context.
This helps explain why pain can change with stress, sleep, attention, fear, expectations, movement, safety, social circumstances, and other factors.
These influences don't mean pain is “all in your head.” They demonstrate that pain is a complex experience influenced by multiple interacting systems.
THE BIOPSYCHOSOCIAL NATURE OF PAIN
Biological
Tissue injury, inflammation, nerve function, nervous-system processing, sleep, genetics, disease, and other physiological factors.
Psychological
Expectations, fear, anxiety, mood, attention, coping strategies, beliefs about pain, and previous experiences.
Social
Relationships, work, social support, culture, healthcare experiences, financial pressures, and the surrounding environment.
IMAGING IS INFORMATION — NOT THE WHOLE STORY
Imaging can be clinically important and can help identify structural abnormalities, disease, injury, or other findings that require attention.
At the same time, imaging findings don't always explain pain severity or disability. Structural changes can occur in people who have little or no pain, and the presence of an abnormal finding doesn't necessarily tell us how much pain a person will experience.
A systematic review of imaging findings in people without back pain found that many common spinal abnormalities become more prevalent with age, even in people without symptoms. The authors emphasized that these findings should be interpreted in the context of the patient's clinical presentation rather than automatically being assumed to be the cause of pain.
This is an important part of communicating pain science: a scan can show a structural finding without that finding fully explaining the person's pain.
The clinical challenge is to interpret imaging alongside the person's history, examination, symptoms, function, goals, and the broader clinical picture.
WHAT THIS MEANS FOR CLINICAL CARE
Assess the Whole Person
Consider biological findings alongside psychological, social, functional, and contextual factors.
Avoid Overinterpreting Pain Intensity
A high pain score doesn't automatically indicate greater tissue damage, and a low score doesn't necessarily mean the problem is insignificant.
Explain Findings Carefully
Imaging and examination findings should be explained in context so that information doesn't unintentionally create unnecessary fear.
Focus on Function
Pain intensity matters, but meaningful outcomes can also include mobility, participation, sleep, confidence, and quality of life.
Look for Modifiable Contributors
Sleep, activity, fear, expectations, stress, mood, social circumstances, and coping strategies may provide opportunities for intervention.
Avoid One-Size-Fits-All Care
People with the same diagnosis may have different mechanisms, contributors, goals, and treatment needs.
COMMUNICATING PAIN SCIENCE WITHOUT MINIMIZING PAIN
Explaining modern pain science requires care. People can understandably interpret discussions of the brain, emotions, or psychosocial factors as meaning the pain is imaginary or “just psychological.”
A better approach is to reinforce that the pain is real while explaining that pain is influenced by multiple interacting biological, psychological, and social factors.
The message isn't: “The pain is in your head.”
The message is: “The pain is real, and we now understand that many systems can influence how pain is produced and maintained.”
RESEARCH & PROFESSIONAL RESOURCES
Imaging Findings & Pain
A systematic review examining the prevalence of common spinal imaging findings in people without back pain.
READ THE SYSTEMATIC REVIEW →Invasive Procedures for Chronic Pain
A review examining invasive procedures used in the management of chronic pain.
READ THE REVIEW →Variability in Diagnostic Error Rates
Research examining variability in diagnostic error rates and the challenges involved in accurate diagnosis.
READ THE RESEARCH →Understanding pain science doesn't make pain less real. It gives healthcare professionals a more complete framework for understanding pain — and more ways to help people move toward meaningful lives.
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