I punched a woden shelf with my right hand when i lost my temper and my middle finger knuckle is swollen snd i can't squeeze my hand. what happened?

Bad idea: We generally call this "testosterone poisoning disease" although female do occasionally do it too probably broke it / the common one is the little finger knuckle which is usually not too big a deal /unfortunately the middle finger is usually worse / go get it checked out it needs an xray.

Possible broken bone: Punching hard objects such as wooden shelves can cause fractures (breaks) of the metacarpal bones in the hand. This is the bone leading towards the first knuckle on your hand when you make a fist. You should ice the knuckle and elevate the hand to decrease swelling and be seen in an urgent care center, er, or orhopaedic surgeon's office to have your hand examined and xrays of the hand performed.

Hand trauma: It's hard to say. There certainly could be a fracture and x-ray would be advised.

Don't know: I would get an x-ray soon to see if you broke it.