Has anyone gone through the diagnosis of this? My pain is in my tailbone, upper back of thighs, butt bones and left hip. All symptoms of SI joint problems. However, my bone scan came back with no inflammation in the SI joint. The doc says that we can say with 100% certainty that it is not SI related. I'm not so convinced. I've been given wrong information so many times by doctors, it's unreal. Anyway, I also have an L5/S1 herniation but the doc says this is not the source of my pain (again, skeptical). The bottom line is that he says he doesn't know what my problem is but suspects that "something happened" during my twin pregnancy two years ago when the hips expanded. So I'm desperate to find out what the problem is. EDITED Nobody can tell me what the problem is. I had two radiofrequency ablations in the spring that removed 100% of my pain but only lasted for 2 and 4 weeks. I had another RA two weeks ago and it only helped minimally, very minimally. So I'm confused by that too. I was so convinced that it is SI joint and now I'm confused. Has anyone else here been through the diagnostic process with this type of pain and how did you find out what it is?