If you feel a dull, steady pain that feels like a band tightening around your head, you may have a tension headache.
If you feel throbbing that begins on one side and causes nausea or sound/light sensitivity, you may have a migraine. Visual disturbances, such as flickering points of light, may precede a migraine headache.
If you feel a non-throbbing pain around one red, watery eye, with nasal congestion on that side of your face, you may have a cluster headache.
If you feel a steady pain in the area behind your face that gets worse if you bend forward -- and if you have nasal congestion as well -- you may have a sinus headache.
Call Your Doctor About a Headache If:
You have a severe headache with vomiting, limb weakness, double vision, slurred speech, or difficulty swallowing. This may signal a cerebral hemorrhage or an aneurysm. Get medical help now.
You have a new kind of headache that you've never felt before. Does it happen the first thing in the morning, bring on vomiting, and then go away during the day? You may have high blood pressure or, in very rare cases, a brain tumor. See your doctor without delay.
You have a high fever and severe pain with nausea and a stiff neck. Does light hurt your eyes? You may have meningitis. Get medical help now.
You are drowsy with dizziness, vertigo, nausea, or vomiting after a head injury. You may have a concussion. See your doctor right away.