Fall 4ft backwards on concrete a week ago

Patient: I had a really bad fall last Monday from a 4ft railing backwards onto the concrete. My lower back was in tremendous pain but the xtrays showed just lower hip and back contusion. It has been a week and I needed to go to the gym to work out. I first got on the treadmill to walk I usually walk 30 minutes a day. This time by 5 mins I had serve sharp pain in below my ribs straight down to my waist. I was told to put heat and ice on it. I tried to rub it but then I couldn’t walk or put pressure on my leg and the pain is super bad. What should I do?

Symptoms: Sever left back pain