A muscle spasm is a protective mechanism designed to reduce movement and aid healing but it can be painful. A muscle injury is called a strain, the severity of which is graded from 1-3. Following an injury to a muscle there is often a Trigger Point (localised muscle spasm). This can last long after the injury itself has healed and can cause sensitivity in the muscle and pain referred to another part of the body.
Your specialist can diagnose Trigger Points through the history of injury and through manipulation of the muscle. Once diagnosed and the spasm released, Trigger Points can be treated. This is usually done through manual pressure that is a little uncomfortable until the point melts. Other treatments can include acupuncture needles or spray-stretch techniques using a cooling agent.