Recently (past six months), I have had a sharp pain in the middle shoulder whenever I do shrugs. Once it starts, I quit doing shrugs for long enough to where it stops hurting. But sure enough, 1-2 months later when I try shrugs again, within two weeks that sharp twinge is back and I have to stop. It feels like a needle stabbed into the middle of my shoulder. Has anyone else experienced this, or know what it is, or know how to alleviate it. Thanks.