I Have Been Having Lower Left Abdominal Pain And Upper

I have been having lower left abdominal pain and upper abdominal pain. I have gone to a gynocoligist and did an ultrasound and my overies are fine. I also have had a CT scan and Hida scan and the came out fine. The lower abdominal pain is getting worse and now my lower left part of my back is hurting. I do have sciatica on that side. Could that be causing my abdominal pain. I also have cramps, diaherra, After I eat my intestines cramp up. I get nauseated sometimes.