Sinker Pains

Ive been throwing a pretty good looking sinker recently, exept its been giving me arm pains. After I throw 2-3 I start to get a sore kind of sharp pain in the inside part of my arm near the back of the elbow to half way up the my arm towards the shoulder. As far as i knew sinker gave little to no pain but maybe I heard wrong.

I throw my sinker like a 2 seamer but I put pressure with my middle finger and snap my wrist down and to the right when I release.

Any help would help as I really would like to start throwing this again as it is my only good payoff pitch.

on a sinkerdont snap your wrist just have it tuned slightly tothe right or left as you throw

putting pressure on the middle finger causes your arm to supinate (turn outwards) which puts stress on the arm

how old r u?

Ok Ill try without the pressure and the wrist snapping. Also im 15 1/2

sinker is grip not wrist