When it happened to me it was like a bolt of lightning striking my lower back. In the midst of some intensive exercise I stopped, ironically, to move a small dumbbell away from my feet to avoid the possibly of tripping on it. I leant over, reached down, and almost at the point of giving it a gentle flick to the right with my fingers a shrieking pain immobilised me. 

I was both dumbfounded and in agony. Putting weight on my left leg hurt, and even standing up straight hurt. My mind was racing. 

One of my instructors was fond of saying "you're only as strong as your back", and my back felt like it was permanently out of action. Was I ever going to be able to exercise again? Was this going to be what life was like for the rest of my life? Had I pinched a nerve, would it always hurt? I was now sweating more from fear than from pain!