I got "addicted" to the swoleness of my biceps to the point where I was one of those guys that was doing those types of curls where I am actually not capable of lifting the weight but will "jump" it up and then slowly let it down in a semi controlled manner. I ended up having the swell, but i also had really terrible elbow pain. I never looked into what that was but I changed my ways.
Sorry to hear about the back problems, i've been very lucky as far as any of that is concerned.
I tried rock climbing only twice. Now THAT is a serious workout.
RE: Fitness Myths: "No Pain, No Gain"