When the body is stressed, muscles tense up. Muscle tension is almost a reflex reaction to stress — the body's way of guarding against injury and pain.
With sudden onset stress, the muscles tense up all at once and then release their tension when the stress passes. Chronic stress causes the muscles in the body to be in a more or less constant state of guardedness. When muscles are taut and tense for long periods of time, this may trigger other reactions of the body and even promote stress-related disorders. For example, both tension-type headache and migraine headaches are associated with chronic muscle tension in the area of the shoulders, neck, and head. Musculoskeletal pain in the low back and upper extremities has also been linked to stress, especially job stress.
Millions of individuals suffer from chronic painful conditions secondary to musculoskeletal disorders. Often, but not always, there may be an injury that sets off the chronic pain state. What determines whether or not an injured person goes on to suffer from chronic pain is how they respond to the injury. Individuals who are fearful of pain and re-injury, and who seek only a physical cause and cure for the injury, generally have a worse recovery than individuals who maintain a certain level of moderate, doctor-supervised activity. Muscle tension, and eventually, muscle atrophy due to disuse of the body, all promote chronic, stress-related musculoskeletal conditions.
Relaxation techniques and other stress-relieving activities and therapies have been shown to effectively reduce muscle tension, decrease the incidence of certain stress-related disorders, such as headache, and increase a sense of well-being. For those who develop chronic pain conditions, stress-relieving activities have been shown to improve mood and daily function.
From the American Psychological Association to read the full article visit. https://www.apa.org/helpcenter/stress-body