Tennis Elbow, in my clinical experience, is a problem of tight wrist, finger flexors and pronators and weak wrist, finger extensors and supinators. I generally don't have a problem with rehabbing this, however, a key point is to REST during rehab. I find they just keep irritating it. I relieve my patients' lateral epicondyle pain with a simple joint mob at the radial humeral joint, watch the video below on how to perform this mob, I don't remember the last time this failed to relieve my patients pain immediately! Give it a shot!