For approximately 6 years I have suffered with an intense burning pain at the base of my pelvis/buttocks. The pain is intensified and prolonged with significant periods of sitting. Mine is not a mobility issue, just a burning-stinging pain. Taking a trip by auto or sitting in church greatly increases the pain. Five years ago, I was diagnosed with sero-negative, non-erosive, polyarthritis (not rheumatoid, but closely related). This diagnosis was based on a lab SED Rate Test. This year, based on the C-Reactive Protein test, I was told that my factors for the inflamatory type of arthritis are within the "normal" range, and the diagnosis was changed to osteo arthritis. Numerous x-rays of my pelvis have shown no osteo damage. My question is how can I have so much pain, if there is no damage or inflamation? The previous diagnosis of an inflamatory type arthritis seemed to be substantianed by the lack of deterioation of the bones, but now I am confused. Each period of the burning pain becomes more prolonged and intense. I am now being referred to a Neuro pain management specialist. If anyone has had a similar experience or has any helpful information in diagnosing and treating my problem would be greatly appreciated. I take 7.5 mg of Mobic twice daily, but I have doubts that it is helping.