Pain from muscle tissue is perhaps the commonest type of pain of all. The muscles are the biggest users of blood and energy in the body and account for the vast majority of nervous system activity. The whole point of having a body is to move; and this is the job of the muscles. Such constant activity needs a certain amount of careful management!
Muscle pain caused by strain and sprain (actual tearing of fibres) is rare, but heals very readily unless there is some sort of impediment to this process. True spasm of muscle is extremely rare and occurs only in underlying bone injuries that the muscle attempts to splint, and in the disease tetanus.
Both muscles and tendons (non-elastic cords that join muscle to bone) are readily injured by repetitive strain or overuse syndromes – in which case the lubricating sheaths of the tendons can also become inflamed. Tennis elbow is a good example of an overuse syndrome – these days mostly caused by computer keyboard use. However, it is interesting to note that most overuse syndromes occur when one is under prolonged stress.
Muscle tissue can fatigue, or it can be inappropriately used and damaged. Fatigue is by far the commonest source of muscle pain, but the odd fact is that most muscle fatigue is due to unconsciously over-used muscle – that is, over-use of muscle is normally the result of stress and tension. To be more accurate, muscles – especially postural, torso muscles – are used to ‘brace’ parts of the body. This is in fact a basic biological survival function when the muscles are stimulated, but at the same time prevented from causing movement. For example if you are irritated, certain muscle groups will want to work to resolve the irritation. Similarly, if you are worried, the muscles will want to work to resolve the worry. This basic biological function is fine in Neanderthal man, but in modern life we are usually trying to resolve our problems without defensive or aggressive activity. However, this frustration in the body leads to muscle tension or bracing, which, if prolonged, will cause pain due to fatigue. This kind of problem is resolvable using muscular relaxation techniques, massage, bodywork such as osteopathy, pain-relief processes such as acupuncture, and of course, other more psychologically inclined stress-management activities, including Somatic Experiencing.
Here is a fairly accurate and popular – if not quite PC – analysis of this problem:
“Stress is – the confusion created when the brain overrides the body’s basic desire to choke the living shit out of some asshole who desperately needs it” (anonymous)