Headaches can be caused by a variety of factors, including tension, dehydration, stress, sinus issues, eyestrain, and migraines. Certain foods, drinks, and medications can also trigger headaches. In some cases, headaches may be a symptom of an underlying health condition such as high blood pressure, concussions, or brain tumors. Understanding the cause of headaches can help individuals to manage and prevent them.

1. Stress and muscle tension: Stress and muscular tension can cause headaches due to the tightening of muscles in the head, neck, and scalp. 2. Caffeine: Too much caffeine can cause headaches in many people, as can abruptly cutting off caffeine intake. 3. Dehydration: Not drinking enough water can cause headaches due to lack of fluids. 4. Hormonal changes: Hormonal changes can cause headaches due to the fluctuation of hormones levels in the body. 5. Lack of sleep: Not getting enough sleep can cause headaches due to fatigue and lack of relaxation. 6. Weather changes: Changes in the weather can cause headaches due to atmospheric pressure. 7. Food additives: Certain food additives, like MSG, can cause headaches in some people. 8. Medications: Certain medications, such as those used to treat blood pressure or depression, can cause headaches.