I just finished a week long flu/cold and 3 days ago I started to get pain in my lower left back similar to kidney stones. I have passed two stones in the past so at first thought I might have another. I took simple extra strength Advil and it takes the pain away but it comes back after 8 hours or so. I did not have a bowel movement for about 3 days but earlier this morning did. Then tonight I had diarrhea. So don't think it is a stone as the pain is not as severe but it keeps coming back to the point where I take another Advil and it again takes the pain away to the point I think it is better but the pain returns.