Don't stop taking painkillers without consulting your doctor. If you do, you may go into painkiller withdrawal. Tell him why you want to stop taking your pain medication, and listen to what he has to say. There may be new alternatives that will work better for you, or he may simply adjust your dose. Don't stop taking your medication on your own.
If you are set for quitting, your doctor will plan a schedule to wean you off of your pain medication gradually and safely. Even with a slow weaning process, you may experience some withdrawal symptoms.