Oaklet! Hi! (this is awesome that you're doing a paper on us!)
For my login, look to your left . . .

The most pain . . . wow that's a tough one. Knees, hips, feet, SI, neck, and fingers. Iritis is no fun, but it goes away, so I'm not counting it.
I'm starting to fuse in the SIs and the feet (not toes or ankles - the joints between those, in the middle of the foot - metatarsals? I think that's what they're called. That's a biznitch) I also have calcium deposits along my finger bones, at the entheses, but it's not to the joints yet.
I've had this evil creature in my body for 13 years, it started very suddenly and noticeably in my left hip at age 10 (september 4th, 1994 . . . 7:30 pm. haha). My brother's AS also started at age 10, suddenly in the left hip. He's fusing in his ribs first.
Thanks for taking an interest in this and writing about it . . .

-Bridget