Most headaches are tension headaches. These headaches tend to happen again and again, especially if you are under stress. They are not usually a sign of something serious. But they can be very painful and hard to live with. Tension headaches can last from 30 minutes to 7 days. If you have a headache on 15 or more days each month over a 3-month period, you may have chronic tension headaches. This type of headache can lead to stress and depression, which in turn can lead to more headaches.