Matthew, I think you and I had the same GI when we first got sick! I had the ulcerative proctitis diagnosis first. Well, duh, if you only use a sigmoidscope you can't see the rest of the inflammation! New doc, better scopes.
Kiki, I think it is a pretty common experience to NOT have a "name" for your inflammatory bowel condition. But I believe calling something "IBS" is just a cop-out. It only means that the DR acknowledges you're miserable, but can't find any "disease" to point to. So then you have a syndrome. An irritable one, too.
I think it is important that there were biopsies done, that they were not conclusive but also showed some problems. Also, that you feel better on the meds.
So I just got some news that I might have ankylosing spondilitis, which is an arthritis that comes with IBD. I've been doing a lot of reading and guess what? Some people get this in their ribs and it causes pain. It is hard to diagnose at the beginning because you need to see bone degeneration on x-ray.
I hope your situation gets less frustrating soon!