Hi, Acer. Ash and Midlife are right, different people have different sensitivities to swingweight. Some might feel 4 points while others won't be able to notice a change until 10+ points.
I would have jumped into your other thread, but it seemed to be mostly about Volkl and I haven't hit with any of their newer models. I did try the C10 Pro for a month and C9 Pro for a couple of months and can compare them if you want me to.
As far as your shoulder, I had some serious shoulder problems (torn rotator cuff) many years ago. While higher swingweight can aggravate wrist problems, I believe you'll find that higher frame weight is what stresses the shoulder the most.
For example, I haven't had any shoulder problems or pain in years. I normally use a PD+. Because of some discussions here on the boards, I recently took several of my classic 12+ ounce mid frames (PS 85, Kramer Staff, POG, Max 200G, Yamaha Black Gold 90) out for a hit a couple of times. During play, I could tell how much harder my shoulder was working. For a couple of days afterwards each time, my shoulder was pretty sore.
Now, the swingweight on these frames was lower than the PD+ by quite a bit. And, they are all shorter (some people feel that extended length frames stress the shoulder). To me, though, the main difference was the weight. I could literally feel the extra stress on my shoulder during play. Of course, I was also having to swing harder than with my PD+'s.
Which brings me to the other important factor for reducing shoulder stress IMO, power. Swinging a more powerful frame really reduces the amount of work that the shoulder has to do, thus reducing stress.
Now, some people claim that stiff frames and tight strings are bad for the shoulder due to shock. Most people's shoulder problems result from stress due to torque, overuse, and/or bad technique, not shock. If you search the forums, you'll find that people complaining about shoulder problems typically are using heavy frames. Their shoulder problems often happen when changing to a heavier frame.
The C10 is a heavy stick and it requires a full swing to get power (though not as violent a swing as any of my "classics"). I finally decided it wasn't the right frame for me because it was heavy and I was having to work just a little harder than I wanted to.
Unfortunately, it seems that the frame characteristics that help reduce shoulder stress (lighter and more powerful) are things that are bad for TE/GE (lighter and stiffer). I ultimately ended up playing 11 ounce frames with tweener power because they were easier on my shoulder. If you have any TE/GE problems, though, you may also want to look for something that's not too stiff. BTW, the C9 was easy on both the arm and the shoulder.
