I have been in a physical conditioning program now for years whereby I have now devoloped powerful muscles that enable me to sit for hours and do nothing. After getting back into slingshot shooting I have to contend that my conditioning program was not conducive nor supportive of slingshot shooting. I hold the fork with my right hand and pull with my left. My left shoulder is sore now and limits the movement of my left arm. Is there something I can do to help that or should I just keep shooting till I get used to it.