This happens to me because of nerve damage and inflammation, and is often accompanied by loss of strength in my hands and elbows. This can and cannot be related to repetitive movements in your arms and shoulders. I go to physical therapy but the problem waxes and wanes. (ugh)
What helps best for me when this happens is alternating heat and cold on my elbows and neck, where the nerve gets inflamed. Beyond that, I recommend flexing and stretching, as well as minor “weight training” with you hands.
Of course, check with your doctor as well.