Before I finally give up on my iPrestige MP, can anyone suggest how to string it (type/tension) so it doesnt burt my shoulder? I have it strung with 17# babolat natural gut @58 and my shoulder starts hurting after about 2 hours hitting with it. I feel a pinch in my shoulder blade area. I currently play with the PC600 which definitely doesn't pinch my shoulder but just want the extra pop from the iP. Thanks.