Hello @murphygirl, Welcome to Connect. I'm sorry to hear the pain returned after the surgery. From what I've read on the surgery around 1 of 5 patients have returning pain.
-- Non-Union and Reoperation after Ulna Shortening Osteotomy:
https://meeting.handsurgery.org/abstracts/2019/HS13.cgi
-- Long-term outcomes after ulna shortening osteotomy: a mean follow-up of six years:
https://online.boneandjoint.org.uk/doi/full/10.1302/2633-1462.35.BJO-2022-0031.R1.
There are a couple of discussions you might find helpful:
-- Both ulnar side of hand problems: https://connect.mayoclinic.org/discussion/both-ulnar-side-of-hand-problems/
-- Ulnar Wrist Pain: https://connect.mayoclinic.org/discussion/ulnar-wrist-pain/.

Have you discussed options with your hand surgeon?