What Causes Right-sided Abdominal Pain, Back Pain And Diarrhea?

Hi I have pain in my right side of abdomen .back pain and loose motion .in my barium meal test appendix is not visualised and in US G of whole abdomen everything is right insipt of dought of appendix .in KUB test small calculas is shown so I am confused either I have stone problem or appendix please suggest me.