The only thing I can think of would be nerve ending damage which can happen while having treatment. Ask your doctor about that. I had it and it is not nice.
which chemo did you get? There definitely is neuropathy that can result from chemo.
E.g., for lymphoma, did you have thalidomide?
Please have your hand checked for carpal tunnel.
Best wishes
This forum deals with breast issues, primarily breast cancer.
I'd suggest you post in the Cancer Forum or the Leukemia and Lymphoma Forum.
Best wishes...