Yes! But that is normal. The pain experience is something that occurs in the brain. When you damage a muscle, tendon or ligamentous tissue, chemicals are released into the surrounding tissues. These chemicals, like substance P, bind with nerve endings and generate an electrical impulse, which travels by special nerve pathways to the brain. Neither substance P nor the electrical impulse, are in and of themselves painful. However, once that impulse arrives in the brain, the brain computes that stimulus together with other information to interpret it as pain. This other information may include someone’s previous pain experiences or the level of stress, anxiety or fear in the person at the time.
An example of this may be; if you were to squeeze the webbing between your thumb and index finger, then you can feel the mechanical compression of the tissues. However, if you squeeze that area firmly enough, then that mechanical compression feeling will become a painful feeling. This pain experience is to warn you that this compression may soon damage the tissues, and so to make a change to avoid that pain. Sometimes the threshold at which that mechanical stimulus becomes a painful stimulus can change. That threshold may be reduced by the presence of inflammation in the hand for example, or it may be reduced due to a previous negative experience you have had with a similar pain. Sometimes this threshold can be reduced to such a level that people develop a hypersensitivity to that stimulus.
Central Sensitisation is the technical term to describe physical, chemical and biological changes within the brain which lead to a hypersensitivity to pain or other symptoms. It is a normal response to any painful stimulus for the brain to change. If pain persists, then these changes can become more pronounced. Sometimes, these changes in the brain remain, even after the damage to the muscle, tendon or ligament has completely resolved. This is when Central Sensitisation can become the primary driver of some one’s pain experience.
Recently developments in the research have provided clinicians with a proven objective measurement tool to enable physiotherapists to accurately assess the presence of central sensitisation in patients with chronic low back pain.
It is possible for Central Sensitisation to explain the entirety of someone’s pain presentation, but highly unlikely. It is very likely that Central Sensitisation is a component of someone’s chronic pain. If the therapist and patient are aware of the presence of Central Sensitisation, and understand what that means, then there are physiotherapy treatment techniques that a patient can utilise. In some patients, there may also be a role for a psychologist to work together with the patient, the physiotherapist and the GP to resolve the pain experience, or at the very least, learn how to manage the pain.