I've started having the same issues. Initially, it was my wrist, but I built up muscles there and thought that was the end of it.
I now have about 50 shaves under my belt, I mean on my face, and my elbow has been killing me for the past week. It only occurred to me today that it is probably connected with stropping. (I'd been thinking I'm developing arthritis).
I've been using both ibuprofen & MSM pain gel (much better than Tiger Balm, btw) but have been interested in the root cause. This thread confirms my hunch. (No, I don't also have a hunch back).