What Causes Swelling Of Right Arm Below Elbow Caused Due To Muscle Stretching?

i cannot straighten my right arm with my palm facing up. I have been swinging a baseball bat and throwing a baseball. I m afraid I have ripped a muscle in my forearm or even my elbow. I have a lot of swelling right above my elbow on the inside of my arm and the underside of my forearm just down from my elbow is very sore.