What Causes Swelling On Fingers?

Hello, for the past few months, my hands have been swollen but not excessively eg.: I can t wear my rings and there is NO joint pain at all. However, when I try to turn the switch on a light in my living room or try to open a jar of something it hurts my my fingers on the surface like my nerves or skin can t handle the pressure of a tight grip. Sorry, but this is the only way I can explain it. I am a 65 year old female, and am pretty healthy and not over weight. 5 9 about 160 lbs. Don t have any major diseases, like heart problems or arthritis or high blood pressure. Any ideas?