I get cluster headaches. They are well documented as the most severe pain known to man, and I get them for weeks at a time, usually twice a year... every year, for the last 20 or so. It's like getting jabbed in the side of the head with an icepick over and over again for hours, just to repeat it every single day for weeks. When I get an episode, I'm usually in tears.
They've been called "suicide headaches" due to people killing themselves to rid the pain.
I take Imitrex injections at $100 a pop just to relieve the pain... they really hurt that bad.
A few lines from
Wikipedia:
The pain of cluster headaches is markedly greater than in other headache conditions, including severe migraines; experts have suggested that it may be the most painful condition known to medical science.
Analogies frequently used to describe the pain are a red-hot poker inserted into the eye, or a spike penetrating from the top of the head, behind one eye, radiating down to the neck, or sometimes having a leg amputated without any anesthetic.
Our patients were disabled by the disorder and suffered from bouts of pain from two to twenty times a week. They had found no relief from the usual methods of treatment. Their pain was so severe that several of them had to be constantly watched for fear of suicide. Most of them were willing to submit to any operation which might bring relief.