Any ideas on what is cause my pain? Abdominal, pelvic, lower back, right side?

I am having moderate to severe pain in my (right side) lower back, pelvic area and abdominal side. It started about a week ago as just light twinges of pain in the pelvis area and has progressed mostly in the past 3 days to the severity I'm in now. I went to the er to get checked out since I don't have insurance and am in so much pain. They did their battery of tests and a ct scan and found nothing and sent me home with a paper that says abdominal pain of unknown cause. Gave me rx for bentyl (sp?) and ibuprofin (sp?). Anybody ever have any pain like this? Its mostly achy but then every so often sharp pain shoots around, especially in my lower back and pelvic area. Please help if you can,