I have pain in my T-7,T-8 area from a weightlifting accident many years ago. It's just in the last few years the problem has escalated to where the pain is getting quite bad. Anyway, without getting into specifics right now, my question is: What is an INTERNAL TENS and how does it work? Pills are not doing anything, PT was a bust and now it's getting so raising my arms is painful. Doc said this internal tens is the next step before any surgery. Any info will be much appreciated!