As a massage therapist, I spend quite a lot of time discussing pain with my clients. I have noticed that it is most often initially described by them as either 'annoying' or 'really bad', but for me to devise an effective strategy to help alleviate it, their pain needs to be understood according to how it registers in their brain, which usually falls in to one of these three categories:
Nociceptive Pain: this is pain caused by tissue damage and typically described by the sufferer as aching or sharp; examples being cuts, bruises, sprains, strains or inflammatory disease. Technically, this pain is tissue-damage signals being sent to the brain by the nervous system and as such will alter with movement, position and load. Massage therapy in most of these cases is about helping people regain movement and function in the affected area as the damage heals; or where healing is not possible, in helping them deal with compensatory muscle-chain issues or guard-muscle hyper-activity.
Neuropathic Pain: this is pain caused by damage to the nervous system itself (including through injury, disease or pinching), and is often described as electrical, stabbing or burning, eg multiple sclerosis, sciatica, whiplash and scar tissue pain. This type of pain is created by damaged nerves mis-firing signals off to the brain. Nerves typically don't heal well, so this type of pain is often chronic and massage therapy often involves alleviating tissue pressure on the affected nerves where possible (including scar-tissue therapy) and addressing hyper-tonic musculature; eg sciatic nerve pain in the legs which can be relieved by stretching and loosening the piriformis muscle which travels through the buttock.
Other Primary Pain: everything not fitting comfortably in the two categories above... cases of over-lap between nociceptive & neuropathic pain; or pain caused by neuropathic dysfunction rather than damage eg fibromyalgia; or pain caused without either damage or dysfunction eg birth contractions.
Psychological intervention also affects what's going on physiologically and can actually change pain patterns. The ever-changing pathways within our brains are surprisingly capable of rewiring, eg with Cognitive Behavioural Therapy or under the instruction of prolonged anxiety, and this includes pain signal interpretation. eg if a person is inclined (for whatever reason) to believe that a light pain they have this week is going to worsen and become debilitating, their brain may start anticipating pain signals to the extent that it continues to register them when they are no longer there. In these cases, genuine physical pain response is triggered without physical damage or neural dysfunction still existing. This is absolutely not 'imaginary pain'. These pain signals register in exactly the same way on brain scans as physical damage pain, making them 100% genuinely felt by the sufferer; but what is going on is that the brain has re-wired to convert movement detection to pain detection under the influence of anxiety. Massage therapy in these cases can often help to 'dial down' that response, demonstrating through pressure and movement (like a physical form of CBT) that motion or function are not affected, or more simply, challenging the neural feedback being received by the brain.
Pain science is a fascinating area of research which is expanding rapidly in line with the rise of new brain-imaging technology and our understanding of disease patterns. Better awareness of the links between our bodies and minds in interpreting pain can only lead to enhanced and better therapies to help us all deal with any type of pain, which after all, is never quite as simple as 'annoying' or 'really bad'.