Try relaxing ur grip on ur mouse, I used to death grip my mouse and I had a similar experience to you (ps. I am noob)
#Having trouble aim training
harsh grove
oak parrot
Make sure your sensitivity feels more natural you should spend some time finding something that doesn't strain you in terms of sensitivity.
you should also think about when you're tensing up and what tasks make you tense if you're tracking and you have to reset your mouse a lot or hold your wrist in a uncomfortable angle a lot maybe turning your sensitivity up would be good.
if youre playing static dots and it takes too much energy to get from dot to dot maybe something higher would be good. and if youre playing static dots and you can comfortable go from target to target slowly you should figure out why and fix it.