So, I was playing Moonlight Sonata and there are some parts that require awkward hand positions, I think everyone experiences that with this song, but after playing my hand feels weird and I went to play another song and I find myself missing notes I don't usually miss. It's most notably because of the part where your pinky reaches out to the right to reach that G note while you're doing triplets with the same hand. I do stretch my hands almost everyday and can do a 9th fairly easily. Is it just something your hands need to adjust to? It's kind of an uncomfortable feeling.
I can't help but think of "N64 thumb," for anyone familiar with video games, which some kids got (sorry, but dumb kids, i never did this) from stretching their left thumb all the way from the center of the N64 controller to the D-Pad on the left because they couldn't figure out to just move their hand. A few people I know have a weird thumb on their left hand where it sort of dislocates itself.