What Causes Pain In Left Buttock And Leg?

I have constant throbbing pain in my left hip, buttock and all through the left leg. It used to pain just above my knee, but now goes right down past my knee. This is constant throbbing and doesn t seem to ever actually stop. I can not lie or sleep on my left side at all because it immediattely makes the pain worse. The results from the Mri s say there is arthritis on my hip some in my back upper and lower. My doctor does not believe a spine doc could help and only would make a referrel to a rhuemitologist. I have been thinking of going to emerg. I really do not want pain meds, at least some answers or real possibilities.