Pain And Swelling In Middle Joint Of Ring Fingers And Nearby Areas, Feeling Of Internal Click On Opening And Closing Finger. Do's And Don'ts?

Hi Doc! This is Ashok, a Male aged 48..My problem is that since last 4-5 days, I am having pain & swelling in my left hand s ring finger s middle joint & nearby areas. This is sudden and without any injury or provocation. Since yesterday, the swelling has reduced but the bone above the joints still pains, particularly when I try using it for anything. Even a soft touch at skin causes sort of burning sensation & pain. Seems, there s some problem in any vein and not in joint. The swelling also varies during the day and sometimes -when the finger is swollen, there is a milk internal click while opening & closing the finger. I m worried. Pls help and also suggest DOs & DON Ts. Regards.