A General Feeling of Disorder by Oliver Sacks [New York Review of Books]
“As an example of this, migraine is a sort of prototype illness, often very unpleasant but transient, and self-limiting; benign in the sense that it does not cause death or serious injury and that it is not associated with any tissue damage or trauma or infection; and occurring only as an often-hereditary disturbance of the nervous system. Migraine provides, in miniature, the essential features of being ill—of trouble inside the body—without actual illness.”
Finally I can show you what I see in my head when I have a Visual Migraine. I get these a couple times a year, but only recently found this site with the amazingly-accurate flash animation.
I honestly do not remember a time in my life when I didn't have headaches Wilco's Jeff Tweedy discusses his lifelong battle with migraines, panic attacks, depression, drug addiction, and the influences of all on his music.