It's a fairly heavy frame. Do you think the shoulder pain is coming from serving?
Shoulder pain can be tricky. Tendinitis can come and go. It might have been the racquet, but it might have been somethng else you were doing. I would be surprised if the shoulder pain immediately went away when you changed racquets, but your post is a little vague on the timing. Obviously, if that is what happened, it looks like the racquet is the problem.