A tension headache is the most common type of headache. It is pain or discomfort in the head, scalp, or neck, and is often associated with muscle tightness in these areas.
Tension headaches occur when neck and scalp muscles become tense, or contract. The muscle contractions can be a response to stress, depression, head injury, or anxiety.
They may occur at any age, but are most common in adults and older teens. It is slightly more common in women and tends to run in families.
Any activity that causes the head to be held in one position for a long time without moving can cause a headache. Activities may include typing or other computer work, fine work with the hands, and using a microscope. Sleeping in a cold room or sleeping with the neck in an abnormal position may also trigger a tension headache.
Read more at: https://medlineplus.gov/ency/article/000797.htm