Originally Posted by KenC
I would also make sure your technique is not the real culprit of your pain. The serve is a very complex series of motions and doing something awkward can put a lot of repetitive stress on joints.
While the 315 is a very comfortable racquet and very arm friendly, it is not a cure (no matter what the sticker on it says) for arm and shoulder pains. The best it can do is only make the racquet a little less jarring on impact when compared to most other modern racquets.
Yep, I came here to post this earlier, but I got sidetracked...
I have shoulder problems, too, and I don't think any racquet in the world would fix it: I tend to hit my toss way too far behind my head (errant/unpredictable toss). Over time, this would destroy anyone's shoulder, IMHO.