What Causes Arm Swelling And Pain After A Fall Injury?

I was playing soccer yesterday, and i fell on my arm. it has been swollen a little bit since it happend. the pain yesterday was a 6, and now its about a 7. The swelling is still there and the pain is still there. It hurts when i move my wrists to the sides and a little bit up and down. And when i move it quickly/hard it hurts. it hurts at the site when pushed. whats wrong with it?