I have been using oxycontin 20 mg. 3times a day a year ago I was taken off oxycontin and put on buprenorphine 12mg a day but my backpain is worse now?

Not for pain. I agree with dr. Aladag's review of your situation. If you were having issues with the oxycontin, in terms of misuse, over taking, unable to wean when clinically appropriate, then it would make sense to convert to Buprenorphine to help with the weaning process. If you weren't having problems with the Oxycontin then i don't know why you were switched to a med not designed for pain control.
Opiate Addiction. Buprenorphine is a partial opioid agonist that is used mainly to treat opiate addiction. It is not a medication to treat pain in the u.S . Precipitated withdrawal can occur when Buprenorphine blocks the activity of other opioids (ie oxycontin), but is itself not enough to give a full opiate effect. Thus, opiate dependent people can feel worse as a result.