What Causes Pain And Bruise On Back After A Injury?

I slipped when I got to the last 2 steps, it was wet. My back came down hard on one step. The same day I had an X-ray. The Doctor said nothing was broken. This was a week ago today. The pain was terrible the first 4 days, it is improving somewhat. And my most painful time is when I get up in the morning, my back muscle goes into a knot. I landed on the waist level part of my back, and the bruising is from the spine and right side of my back. I can t tolerate much pressure on the right, even a pillow hurts. I ve never had an injury like this before, and I can t help but wonder if there could be something else wrong. There is no blood in my urine or stools. And no problem going to the bathroom. I m a senior.