chronic collateral ligament injury in PIP joint

In a climbing fall almost 2 years ago, I had a minor fracture of my left ring finger which caused the ulnar collateral ligament at the PIP joint to partially be avulsed when the side of my finger struck a bolt. The finger was splinted for 6 weeks and as I began to increase the intensity of climbing in the past year, the finger has began hurting almost all the time during and after climbing. I had X-rays and an MRI of the joint, but the doctor didn't find anything very wrong except tthe small bone fragment on the partially avusled ligament and said the joint is stable. He also mentioned that there was mild synnovitis in the joint. I got a cortisone shot in the joint which barely helped if at all. I have tried resting it for several periods up to 4 weeks, squeezing foam balls and gripmasters, icing, taping, etc. with little success. Ibuprofen helps a bit. When I stretch the joint to the fully extended position I can feel a little popping action in the joint. the pain is mostly on the ulnar side of the joint when palpated and on the top and on the ulnar side when crimping. the joint is most painfull when half crimping and least painful when doing open handed climbing including shallow 2 finger pockets. Do you have any suggestions on what I can do to improve my injured finger?