Hi Norma,   I'd really have to say you need to consult with a physician about your symptoms. There can be many reasons for the several symptoms you describe but without knowing your history, blood work, and having other tests done to rule out certain illnesses I can't necessarily say what you are dealing with nor what might help you.   Thin stool could simply be from a lack of proper amounts of fiber in your diet or it could point to IBD (or possibly IBS.) Left sided colon pain can be common in patients with UC - ulcerative colitis, but back pain is less common. So, again, hard to pin-point what is causing which pain.   Really, the best advice I can give is to consult with your doctor.   Cheers, Elizabeth