I used to get frequent headaches, but not the kind that Imitrex would help....I can't have additional serotonin....I also get projectile vomitting with the headache.

This is not a big brain answer, however, I have had the same phenomenon that you have had......

also, 'migraneurs' are 'overrepresented' in those with autonomic dysfunction, and autonomic dysfunction is often small fiber neuropathy.

Autonomic dysfunction or autonomic neuropathy is a small fiber neuropathy, which can involve gastroparesis or GI motility problems, smooth muscle function disorders, vomitting, cardiac arrhythmias, POTS, vascular related phenomena such as as vasospasm or vasodilitation, hypotention, labile hypertentsion, visual disorders and on and on. It it is an involuntary function, the autonomic nervous system is involved. The autonomic nervous system is peripheral, however, the nervous system is inextricably linked to the CNS.

I have not had a migraine like headache in over a year, knock on wood.

Hope the info helps. I wish there were better answers.