I've had abdominal pain on my left side since last summer my doctor said its ibs but i don't think this much pain is caused by ibs what else could it be?

Go back to your doctor.: Certainly irritable bowel syndrome can cause a significant amount of pain in the abdomen – that is one of the primary symptoms of ibs. However, if your pain remains severe and is not being treated well with the regimen that your doctor suggested, then further changes need to be made in your treatment plan. Go back to see your doctor or ask to be referred to a gastroenterologist.