I'm working on knitting backwards (something new for me) and I noticed my hands and wrists were complaining. I have to pay attention to how I'm holding the needles, doing something new I find I'm trying to get a death grip on them like I did when I first started knitting. So, I'm thinking that you might see if you can loosen your grip on the needles and pay attention to how you're moving your hands, wrists, arms as you knit. Just a thought based on my current new experience.
I should never overestimate my basic arithmetic skills.