Index finger pain

I had shoulder surgery 4 months ago with an Intrascalene Nerve Block and general anesthetic. Since the surgery I have had continous swelling and pain in my index finger only. At one point when moving my arm I had sharp pain in my shoulder and instantainiously my index finger went completely numb. The feeling came back slowly after about 20 minutes and has not repeated but since then for the last two weeks the pain in the finger, especially at the base has been worsening.  I never had any problems like this before the surgery. Is it possible that the nerve block has caused this and can I expect it to go away with time? If not, what other causes could there be for this?