What causes a headache?

Headaches can be caused by a variety of factors including: stress, lack of sleep, dehydration, eye strain, sinus pressure, certain foods, hormonal changes, and some medical conditions.

Other potential causes of headaches include: migraines, tension headaches, hypertension, exposure to loud noise, poor posture, and neck or back problems. Some medications can also cause headaches as a side effect. If a headache persists or is severe, it's advisable to see a doctor.