Pull-up/Rehab Question

I don’t know if this is the right place to post this but here goes…
In September last year I suffered a neck/shoulder injury while training for an MMA fight here in NZ. The left side of my neck seized up in the upper trap area and restricted my neck movement somewhat. I have done this before in the past and the problem has only lasted a week or so then the pain would subside and movement return to normal.

This time however the pain lasted months and spread down my arm. After lots of different treatments I finally started feeling better and eventually the pain was gone. A nerve conduction test suggested nerve root damage at C5/6 I think?
Anyway on to my question, When I try to do a wide grip pull up which I had no problem with in the past, my body pulls to the right side as if the muscles aren’t firing properly in the left side? Don’t think I can curl as much with my left arm either but haven’t tested for ages.
Can anyone help me on how to rehab, who to see, or even another forum to post the question on?
Will be surprised if anyone can be bothered reading all that and very appreciative of any advice.