I started doing my extended family genealogy after seeing the PBS show about it.
So I tend to get drawn into it for long stretches of time and days at a time.. not good for me or my elbows...
Plus it's been mostly damp and rainy so not much to do outside yet..

My elbows & neck & shoulders.. will start to complain so I know I have to stop doing what I'm doing. And take steps to counteract the neg effects of the sustained computer time.

Basically for me sx are originating in the neck/shoulders and not really the elbow - it just gets the down the chain effect from the tight neck.
My fingers loose dexterity and forearms feel tightness also.
It's all related...

Luckily the weather is supposed to change for the better so I can get outside and take a break from the family tree work..