Bob,

Take it slow and easy when you ride tomorrow. You may have some back spasms, caused by the rib problem. I had a similar injury when, a number of years ago, my bike went out from under me and I fell hard on my left side. I probably cracked or broke a rib then. The next day I went out and got into a ride with another guy, who tried to beat me because I was riding an old ten-speed and he had a very new, expensive bike. We hammered for awhile, and during one I felt a "ping" in my back. I had actually torn the muscle, and to this day that area is more prone to back pain than any other spot on my body. Those back spasms are telling you, "Don't move in this manner right now. We're protecting a very sore part of your body." Heed that warning, and take it very slow and easy for the next few weeks.

John