A headache is pain or discomfort in the head, scalp, or neck. Most headaches are due to tension, migraine, or a combination of the two. Serious underlying causes of headaches, like a tumor or a stroke, are extremely rare, despite the fact that many people worry about these possibilities.

Most people with headaches can feel much, much better by making lifestyle changes, including learning ways to relax, and occasionally by taking medications.

See also tension headache, cluster headache, classic migraine headache, and common migraine headache.

Tension headaches are due to contraction (tightness) of the muscles in your shoulders, neck, scalp, and jaw. They are often related to stress, depression, or anxiety. Overworking, not getting enough sleep, missing meals, and using alcohol or street drugs can make you more susceptible to headaches. Foods that can trigger a headache include chocolate, cheese, and monosodium glutamate (MSG), a flavor enhancer. People who drink caffeine can have headaches when they don't get their usual daily amount.

Other common reasons you may develop a tension headache include:

• Performing an activity that causes you to hold your head in one position for a long time, like using a computer, microscope, or typewriter
• Sleeping in a cold room or an abnormal position
• Overexerting yourself
• Clenching your jaw or grinding your teeth

Tension headaches tend to be on both sides of your head. They often start at the back of your head and spread forward. The pain may feel dull or squeezing, even like a tight band or vice around your head. The muscle tension often begins in your shoulders, neck, or jaw before spreading to your head. Therefore, these areas may feel tight and sore as well.

Migraine headaches are severe, recurrent headaches that are generally accompanied by other symptoms like visual disturbances or nausea. They tend to begin on one side of your head, although the pain may spread to both sides. You may have an "aura" (warning symptoms that start before your headache) and usually feel a throbbing, pounding, or pulsating pain.

Other types of headaches include:

• Cluster headaches are sharp, extremely painful headaches that tend to occur several times per day for months and then go away for a similar period of time. They are far less common than migraine or tension headaches.
• Sinus headaches cause pain in the front of your head and face. They are due to inflammation in the sinus passages that lie behind the cheeks, nose, and eyes. The pain tends to be worse when you bend forward and when you first wake up in the morning. Postnasal drip, sore throat, and nasal discharge usually occur with these headaches.

Headaches may occur if you have a cold, the flu, fever, or premenstrual syndrome.

If you are over age 50 and are experiencing headaches for the first time, a condition called temporal arteritis may prove to be the cause. Symptoms of this condition include impaired vision and pain aggravated by chewing. There is a risk of becoming blind with this condition. Therefore, it must be treated by your doctor right away.

Rare causes of headache include:

• Brain aneurysm -- a weakening of the wall of a blood vessel that can rupture and bleed into the brain
• Brain tumor
• Stroke or TIA
• Brain infection like meningitis or encephalitis