Hello, thanks for using health care magic. Stating your age would have been of help to an extend. However, from the information you have given, You basically have two problems, -the back pain and -bloody stools Bloody stool is not a symptom of arthritis and it is rather a common symptom in digestive affections including; -infections, -inflammatory bowel diseases -tumors etc. Bloody stool is a severe symptom that requires adequate investigation in order to get the cause at the earliest time possible so as to give appropriate treatment. Back pain is a common issue especially in elderly. It could be due to disc problems or wearing out of vertebrae due to chronic use and age. You will need to revisit your doctor for detail examination and for tests including; -X-ray or CT scan of vertebrae to investigate on the back pain -Colonoscopy, stool exams etc to investigate on the the bloody stools, -General tests such as ESR, complete blood count etc. Hope this helps you Best regards Dr Achuo