Myofascial pain syndrome is caused by a stimulus, such as muscle tightness, that sets off trigger points in your muscles. Factors that may increase your risk of muscle

trigger points include:

• Muscle injury. An acute muscle injury or continual muscle stress may lead to the development of trigger points. For example, a spot within or near a strained muscle may become a trigger point. Repetitive motions and poor posture also may increase your risk.
• Stress and anxiety. People who frequently experience stress and anxiety may be more likely to develop trigger points in their muscles. One theory holds that these people may be more likely to clench their muscles, a form of repeated strain that leaves muscles susceptible to trigger point