Bad pelvic pain 5 months Post-Partum, advice?

I'll be 5 months post-partum in a few days but these last month I get random pelvic pain that is really bad and only on one side. Its a pressure/sharp pain, I'd compare it to labor sometimes. If I'm lucky 3 tylenol will take it away after an hour or so. I was diagnosed with PCOS back in 2009 both ovaries were poly-cystic. Then switched to a new OB/GYN in early 2011 and he did a scan and seen no cysts (after a year on Metformin) so he said I didn't have PCOS afterall. By the end of 2011 I was pregnant and everything went smooth. Easy labor, normal vaginal birth, only a few stitches, easy recovery. I have been getting my period since 7 weeks PP. Its also never during intercourse, which is when I think it would happen most. Could it be some cysts coming back or just a normal post-partum thing that'll clear up eventually? I called my OB/GYNs office and they can't get me in until Feb.19th. Any advice is welcome.. TIA!