I would call the surgeon and ask if this is normal or not.

I hate to mention it but .. sometimes RSD/CRPS can happen after injuries or surgery.
You may want to read on our forum for that , just to be aware of the possibility , so you can watch for those sx.
be sure to check out the sticky threads above the main thread list-
http://neurotalk.psychcentral.com/forum21.html

A knowledgeable MD,PT , surgeon, should be aware of it , I hope, and be able to help sort out if it really is the ulnar nerve or something else going on..

I would hesitate, and get more opinions if anyone mentions another surgery right away. Unless they can prove it with testing /imaging that clearly shows a real cause.

We have had other musicians here before, the long practice hours, positions, and as kids they may not be taught , or practice the best body ergonomics...
Some people are just more predisposed to conditions like this..