Hi, Welcome to health care magic, I have read your queries and will be answered by me. Since you are suffering from ulcerative colitis and you have been prescribed mesalamine (Lialda) is actually an anti-inflammatory drug used to treat inflammation of the digestive tract like in case of inflammatory bowel disease (ulcerative colitis and mild to moderate Crohn s disease). It does not cause swollen ankles or legs and not even back pain. Swollen ankles and legs should be evaluated further by examination and some relevant investigation like complete hemogram,ESR,color Doppler of respective leg. You must consult your treating gastroenterologist for complete medical history and thoroughly clinical examination. Severe back pain is quite common among people. 1) Back muscle strain is one of the most common causes of mild to severe lower back pain. 2) Lifting a heavy object, twisting, or a sudden movement can cause muscles or ligaments stretch or develop microscopic tears in muscles. 3) Wrong posture or lack of stretch breaks during the work Ensure that you maintain an appropriate posture while working or sitting or walking. Take frequent stretch breaks and drink lots of water. Do not lift heavy objects, especially after bending down.Eat a healthy wholesome meal which should satisfy your minerals and proteins requirement. Take pain killer medications (ibuprofen or tramadol) with muscle relaxants like Robaxin (methocarbamol) prescribed by your family physician. You can also apply over the counter pain killer gel or ointment for faster relief. Mostly,this kind of pain subsides within 3 to 5 days with medications and rest. In case of pain persists then see your doctor urgently for further work up. Regards,