What Could Abdominal Pain Below The Pelvic Bone Be?

I went to the ER on monday night and got no definite diagnosis, I am being sent to my PCP tomorrow for further testing. The Dr from ER sent me home with antibiotics for a mild UTI, but the CT scan they done revealed a further problem. It was a scan of my abdomen and pelvic area. It was a pain in my right lower side, right below my pelvic bone. They are thinking it was my ovaries, but are not sure right now. What could this possibly be?