The diaphragm is the major muscle of respiration. It’s main action is to increase the volume of the thoracic cavity during inhalation. Trigger points form in this muscle due to asthma, emotional overload, disk problems, weak abdominals, hyperventilating, smoking, and poor posture. When trigger points form they can cause a wide variety of symptoms including hyperventilation syndrome, heart and lung issues, as well as a “stitch” pain when running or exercising.