I Slipped On The Garage Steps And Came Down Hard

I slipped on the garage steps and came down hard on my mid/lower back on my right side. Horrible pain in my muscles, but I can press all around and I don't seem to have any inside pain. It's been a little over 2 days and I am getting better, but I haven't had a bowel movement and I'm pretty regular. No blood in my urine and no pain urinating. I'm 64 but do 5 days a week of 1 hour spin classes and 45 minutes of weights 4 days a week and have for years. I am taking a lot of ibuproben. Should I worry?