I have had severe back pain for several months now. Investigations are ongoing. The doctors have yet to find effective pain relief for me without bad side effects.
I heard about TENS and checked out where to get a machine. I found one for £9.99 on eB** and bought it just to try it out. It provides much appreciated relief while it is running but sadly the effects don't last. Still nice to have 30 mins without the pain. You can get units which cost in the hundreds but I know if they are any better.