Mobility issues

....show up in unexpected places. Somehow I noticed that my right thumb can't close as far as my left. I've been stretching to try to get the mobility back, but it's not happening yet.

Check out the difference in how far my thumbs are closed;

I'm closing them as hard as I can. I can bend it a little further by squeezing it inside my fist, but I can't make it go any further on it's own strength.