What Is The Painful Knot On The Underside Of Forearm?

In September of 2013 I suffered a broken right ulna in a car accident - what was called a punch fracture near the wrist. After taking an extra long time to heal and being in a cast and brace for over three months, I set about to rehabilitate and strengthen my grip, wrist and arm as well as restore flexibility. I still am not able to completely rotate my hand up or down in the supinated or pronated position. As a result, I have given myself a case of tennis elbow because extra torque is being placed on the elbow when I try to use my forearm or do arm exercises and stretches in the gym. I have been going to a physical therapist as well as wear a tennis elbow brace. It s gets better for a while and then gets aggravated again. I have developed a strange knot on the flat underside of my forearm up near the elbow that is very painful when palpated, almost like a searing pain as if something is torn. Neither my doctor nor my physical therapist can tell me what this knot is or what has caused it. The therapist has been using dry needling all around the elbow and forearm to help with the tennis elbow, but the knot won t go away. I could not see on anatomy diagrams that part of the forearm near the elbow to see if it could be a ligament or a nerve ending that may be aggravated. Do you think you could give me an idea of what this knot is and what to do about it? Also, if the hand does not get to the point of being able to rotate up and down completely, will the tennis elbow remain a problem? It has been suggested that I seek a second opinion with a hand specialist as the orthopedist who treated the broken arm told me he had done all he could do for me! Thanks, Ellen Picket