Hey s-creek,
I had this problem last winter. My right elbow got so bad I couldn’t even pick up a 6-pack. Then I decided it was the grip shifters and switched to the thumb/trigger shifters and the pain went away within a few weeks. This winter (I ride a road bike in the summer) I’ve had zero pain. You didn’t say what sort of setup you had, but thought I’d post this for others who may have a similar problem.