What type of pain have you? What meds are you taking now? You should really look into going on meth; it seems to be very difficult to come off. You should check out the substance abuse forum if you've been sbusing your pain pills.
You can't just "think" about going on Methadone for a week. Check out the rules and regs. at a Methadone Clinic. You do realize that you can't "use" the Clinic and still possibly take whatever unnamed drug you were previously taking if it doesn't work out? Please go to the Metadone Clinic and be advised because YES, it could possibly be a great help to you if you don't get hooked on the Methadone like many people do! Good luck sweety! I'm praying for you to be led in the right direction!