I've had shoulder problems until I finally had surgery to get rid of inflamation I was experiencing. I have no idea how that compares to your situation, whatever it is, though my shoulder never had a tear. I had problems on over-hand shots (serves, over-heads), but not on groundstrokes or volleys.
I think a shoulder-safe frame is generally one that is not over one's swingweight threshold, also one that is not balanced too high (toward head-heavy, especially into the head-heavy half of the frame).
I have no idea about you or your playing, but if your frame has a swingweight of 342, even if that is strung spec, then it's definitely on the swingweight heavy side of what's out there. I had shoulder problems with even a very flexible, head-light frame that I even made both more head-light and heavier because, I think, one day I just injured my shoulder and I was still trying to play with the high-swingweight frame in the time afterwards.
Sure, a more flexible frame in a make-believe world can be good because it absorbs more shock, especially when it is compared to very stiff frames around RA70, but you also generally need to swing harder to move the ball, which creates more shock that needs to be absorbed, especially when you're framing the ball due to swinging harder than is natural for you. Another thing, a flexible frame along with a relatively dense string pattern can make it harder to hit some shots, like perhaps a slice serve out wide. At least, that particular shot is a lot harder for me with the flexible/dense Prestige Classic. This makes me over-swing in those instances. Really, a frame with RA66 (at the throat) isn't that stiff, unless the frame feels more harsh than that, and/or if the frame is relatively stiffer in the hoop (up top).
A balance that is too high will make the frame want to carry through the air more and will move the handle part of the frame around more. Visualize how a hammer were to move through space if thrown. The handle would be all over the place. With a tennis racket, your hand is attached to that handle, back and forth, dragging your arm around like a rag doll attached to your shoulder. It's subtle, but that is what seems to happen.
In short, as far as your frame goes, I think, if anything, the high swingweight and a high balance are holding your shoulder back, though I don't know you or your playing.
As far as specific frames for you, it's also hard to recommend something when you don't say what you want out of a frame. I think most Head/Völkl frames will feel much different from your Wilson Hyper Hammer. A Babolat Pure Control might be up your alley; it is heavier, a lot more head-light, and has a lower swingweight. It's still powerful and though stiffer, doesn't feel too harsh with it's curved grommets all around. Though if you're really scared about your shoulder, you might want to check out one of the Pro Kennex Kinetic frames; they have had great reviews from people with some sort of injuries.
At the very least, your string/tension shouldn't be bothering you much, unless you're playing with stringjobs that are a few months old, which I kind of doubt. A teammate on the woman's side of my DII team plays with something like a Wilson n4, sounds similar to your frame, and breaks strings constantly.
Anyway, good luck to you. It must suck to get an injury now since you probably want to be ready in a few months.
