I fell on stairs. My feet slipped out and I fell back onto to top half of buttocks and the back hard so that my middle back hit hard in the muddle across a step. I can move around but the pain in the middle of my back is pretty bad. A severe ache not a sharp pain. Some pain in right back side of back too. Just happened 30 minutes ago. Took moron and icing it. Do I need to go to ER bc of back pain?