The body patches irritation. In this instance, it's a Deviated Septum. Here's an excerpt from the migraine info:

HOUSTON, Texas June 27, 2001

Local facial plastic surgeon and otolaryngologist, Kevin R. Smith, M.D., F.A.C.S., of Smith Cosmetic Surgery Center has successfully treated numerous patients suffering with recurrent and chronic migraine headaches with a simple 30-minute procedure. On average, Dr. Smith cures 15 to 20 chronic headache sufferers annually by repairing the patient’s deviated septum with a procedure called septoplasty.

“Over the years, I have found that one simple reason for recurrent or chronic headaches and migraines is a deviated nasal septum,” said Dr. Smith. “Throughout life, the nose can be traumatized resulting in a septal bone spur. When the nasal tissues swell and touch the bone spur, it often refers pain to the forehead and temples. This cause of chronic pain is often overlooked.”

A large number of headache sufferers would benefit from a nasal/septal exam and the septoplasty procedure. Repairing the deviated septum is a relatively simple procedure, which takes about 30 minutes. During this surgical procedure, the bone spur is removed and the septum is straightened so the contact point that creates the headache is eliminated. “Many of my patients experience dramatic results after the procedure,” said Dr. Smith.