Are there any procedures other than a colonoscopy that can be done to discover problems with bowels?

I damaged something by drinking an immense amount of beer in 2009. Now I have occasional incontinence and farts and bowel movements often feel identical. I have been eating well the past year, eating foods high in fiber and eating small meals throughout the day and that is easier on my digestion, but i had a colonoscopy a month ago and the doctor did not find anything. The doctor was really not helpful, and I was really hoping to find the problem so I could work to fix it. The doctor just told me to eat more fiber so i've been taking Benefiber(fiber supplement) and if anything I am less regular. I might have ibs and BMs come out at an angle, but my doctor basically acted like I was a moron. Any suggestions other than "take more fiber"?