When I was in high school, I don't know exactly why, but head aches became frequent, and migraines the norm. I was plagued with at least one head ache a week--it was seriously that regular--and a migraine came just about once a month. Usually, I was blessed with low-end migraines; painful, certainly, but nothing to cry about.
But two instances are burned into memory that were very tear-inducing.
The first was the one time the migraine hit me suddenly. It was just about the most painful thing I had experienced in my life, and to date still is. I had to lie down because the pain was so excruciatingly crippling. Lying down on a soft, comfortable pillow actually made the pain
worse, not better. I had my TV on, and the noise made the pain even worse. The light in my room due to my having nothing but light curtains made it all the worse; years later my parents finally deigned to grace my room with blinds; too little, too late, as I moved out shortly thereafter. But not only did the light hurt my eyes, but when I covered my closed eyes to shut out all light, the pain
still got worse. Aspirin didn't help. It was the first time in my entire life that I seriously thought my head was going to implode; I could actually feel my brain pushing outward against my skull, which of couse made the pain even that much worse.

I had to bear with it for hours, and the pain was so strong and so constant that it reduced me to tears.
The second instance of a painful migraine actually beats out the first, not because of the pain itself but the longevity. You don't know pain until you have had a 48-hour migraine (unless you're a woman; I always take a backseat to someone who squeezes a watermelon through a dime-sized hole, even if DW thinks it was a positive kind of pain

). I woke up with it, I went to school with it, I came home with it; turns out, I was actually sick, and the migraine was a symptom. The pain wasn't quite as excruciating as the time I mentioned above, but it wasn't too far off, either, and it stayed with me for 2 whole days. Then, it went away, and then it came BACK! And for two more days still! Two consecutive 48-hour migraines. It's a long-lived agony.