Hi. I started with rsd in my right wrist and hand and elbow and shoulder. It then spread to down my right leg and right foot to my other foot and calve and left wrist and left hand. I've also had it spread to parts of my stomach due to multiple surgeries I've had. I've never had it in my back though. Maybe try seeing if your neurologist or pm dr can help try to find out what it is. I hope you can find out so you feel better soon. Take Care.