Basically I've been going to the gym for the past 2-3 months and two of my friends said that I may have a pinched/trapped nerve. When I do overhead exercises with the dumbell I'm perfectly fine and can do it but my left side is very weak and I find it hard to push the weight up. I do a lot of this overhead exercise which is to bend and flex the elbow 90 degrees but I find it very difficult on my left arm. Is it bad to carry on doing this because I do it a lot at the gym and how can I fix this?