I Landed Hard On Steps Last Weekend And Hurt My

I landed hard on steps last weekend and hurt my lower back. It is quite bruised and there is a large amount of swelling that does not seemed to have gone done at all. I did go to the doctor five days ago and he xrayed me and said there were no fractures. He also gave me a prescription for painkillers. I am concerned about the swelling though, shouldn't it have started to go down by now?