Hi. Thanks for your query and an elucidate history. The probable causes of pain on the left side are : For me to give you a more specific diagnosis, I would request you to provide me an additional information: Is it the whole / lower / upper part of the abdomen that is aching? Any associated symptoms like change in bowel habit (Stool) like loose motion, mucus, blood, hard stool? Any other problem like burning urination, fever, chills, vomiting, or so? This will help me to help you more. As per the history you have provided the commonest causes of aching in left part of the abdomen for 3 days are: - Colitis - Left ureteric stone with colic - Kidney or pancreatic problem if the pain is in the upper left abdomen. - Less common problems can be decided as per the detailed history, clinical / physical examination by a Surgeon and investigations as needed.