I am on pain killers and haven't had a bowel movement in over 8 days, is there something wrong?

Slow transit time: Opioids slow transit time and that may be a reason you have not had a bowel movement. Take some otc laxatives if yo have no success see your doctor.

Opioids: I agree with the previous answer. I would like to add that when choosing a laxative, be sure to select one that is a stimulant laxative such as one that contains senna. Simply using a stool softener alone will normally give you results if you have been on opiates. If you do not get results, be sure to contact your doctor.