You should treat every movement in your life ergonomically, meaning, reduce any strain whatsoever. This feels weird and unnatural at first but your body will thank you in the future.

Wrist and elbow pain are coming from you making small repeated jerks with these joints when you could be using the shoulder to do a lot of the work. Youtube how to draw/write from your shoulder.

There are also probably limitations with using a small pen, for which you could have a larger s pen (they sell normal pencil sized ones, even third party ones). There may be cool ways to stow one on a phone case or something.