Muscle tension can be a big contributor to headaches.
This alone may trigger a headache. When you have a headache, your muscles tense up even further because your natural instinct is not to move your head. If you're a frequent headache sufferer, over time your muscles may become shortened, chronically fatigued and even irritated. As you can imagine, this can easily become a self-perpetuating situation. Gentle neck and shoulder exercises may be used to relax and stretch strained, shortened muscles.