The good news: The doctor knows what it is, and, while not common, it is treatable.
The good news part deux: tickets to see Joe Satriani!!!!! (Thanks, Stultz and Gav!)
Apparently, what I have is chronic paroxysmal hemicrania. It's fairly rare in the US, but has a pretty simple treatment (mmm, new meds!) and isn't life-threatening or anything. To be sure, the doctor ordered some blood tests and I'm going to have an MRI in the next couple of weeks (they've got to call to schedule). So, yeah.
Here's hoping this'll finally take care of things. Woo and ha, I say.