Brenda Morgan recalls headaches so bad that "if I'd had a gun, I would have shot myself."
Kathy Aronis has lived with "some sort of headache" almost daily for 20 years.
Morgan, a nurse, and Aronis, an office manager, are among 28 million Americans who live with migraine headaches. A total of 45 million suffer from some kind of recurring headache.
Migraines, linked to abnormalities of blood flow in certain parts of the brain, can bring on nausea and light flashes, can last hours to days and can be triggered by foods and environmental conditions that don't affect others. The usual suspects include bright lights, loud noises, red wine, chocolate and aged cheese.
Migraines can be hormonal, hitting three times more women than men. They tend to run in families.
Less debilitating than migraines, but more common, are chronic tension headaches, affecting 40 percent of the population. They're more dull ache than throbbing pain, like a tight band squeezing your head.
Causes include bad posture, neck strain, squinting, stress and bending too long over a computer.
Other common headaches are sinus headaches and cluster headaches, which usually hit behind one eye. Combos include tension-migraine headaches and sinus-migraines. Rebound headaches are caused by taking too many painkillers for headaches.
Headaches are one of the most common medical complaints, claiming 150 diagnostic categories, according to the National Headache Foundation. Yet they are invisible and almost impossible to measure, said neurologist Dr. Allan Bernstein.