Dr 8a

Strain in forearm

Hi! lately iv'e been feeling a strain in my left forearm. Last time i was at the gym I tried to find out what caused this strain. What I found was that, when I pinch or crimp with 3 (4 with thumb) fingers, and let the little finger hang, i get the strain. When I pich without my little finger, the little finger naturaly pulls down, as it would if i'd was to use it in the pinch. This is where it hurts. I found that i don't even has to hang in the hold but just stand on the ground pinching and dropping the little finger and it strains. As a test, my friend lifted my little finger when i pinched and the strain was gone (in that position). The pictures shows how the little finger drops and where in the arm it strains. Is this an injury? Starting of an injury? or just weakness?  ;) Is there any exercises i can do to get ridd of this problem?