First off, make sure you got that grip settled onto the pad of your thumb.... not settled into your palm. If you're doing it in the palm you'll get more torgue and odd hand pressures. It won't take long to get the hang of shooting off the pad UNLESS, you're over bowed or your draw length is too long. That would be my next thoughts, your draw length may be wrong. Assuming they're all correct, take your grips off your bow and use some of that vibration wrap that Sims(the leeche people) make. Wrap it around your rise where the grips were. It makes your bow warmer to hold in cold weather and really is nice to shoot from.