Your head is aching and you can’t focus. All you want to do is lie down in a quiet, dark room until it passes.

Nearly every adult has had a headache at some point in life. Defined as pain in the head or upper neck that originates from inflammation, over-activity, or irritation in the tissue surrounding the brain, skull, sinuses, eyes, ears, or nerves in your head, a headache can feel like a sharp or dull pain, be constant or come and go, and throb or pulse. Depending on the cause of your headache, some last a few minutes, others can last several weeks.

There are three main types of headaches (primary, secondary, and other), and each kind has different triggers. Primary headaches include migraines, tension, and cluster headaches. Secondary headaches are often due to an illness or injury.

Here are three examples of both primary and secondary headaches and common triggers for each.