So I had laid off walking for several days, trying to give myself some healing time. My back seems to be getting better, but I have this new knee pain, which started on one of my walks. I thought I had sprained it a bit too much and was trying to let it heal on its own. Then I thought, listening to Dr. Sarno's words, exercise can't hurt you. So I walked yesterday again and now my knee is really throbbing. Before it only hurt when walking down stairs, now all the time. How does that jibe with what Dr. Sarno said about exercise? I am confused.