My Left Index Finger Started To Lock In A Partially

My left index finger started to lock in a partially closed position, with moderate pain. It "pops" when I move it. Finger is swelled, movement restricted, and pain is most noticeable at night. I've had not trauma injury that I recall, but this has gone on for over a week now with no sign of letting up. On occasion I have felt similar feelings in without the locking in other fingers, mostly at night.