Definitley had severe bone pain that lasts about 7 to ten days total. Was severe enough to send me screaming in agony to the E.R. Doctor has since prescribed pain medication that I take week of injections and typically a couple of days after and it seems to work. Medication is Percocet. Pretty strong but I couldn't tolerate the injections without it. I felt like a vice grip was squeezing my spine. It was horrible. Have to tell you though, I would prefer the agonizing pain to the Interfuron treatment any day.