Most lifters don't create enough full body tension on the bench press. The best way to protect the shoulders is by optimizing the position of the entire body.

Taller lifters have ability to use full body tension by driving their feet hard into the ground. Externally rotating the hips with full glute and hamstring contraction can place the pelvis into a stable position and allow for better force contact through the feet into the ground, and butt into the bench. This proximal stability will create a more solid position for the shoulders during the press.

But that strategy doesn't work for shorter lifters. This one does: simply elevate your feet. The standard bench height is a common problem for many lifters, especially those under about 5'8", due to the lack of solid ground contact with the feet and position of the hips and pelvis.

Using boxes or weight plates, elevating the "floor" under the feet allows the hips to be positioned in a more neutral alignment. The lower body and pelvis are more able to create spiraling torque and tension.

I realize that dragging over a few 45 pound plates to place under your feet every time you bench press is a pain, but it'll be worth it when you finally feel what it's like to bench press with proper stability and tension through the entire body. It'll translate into less shoulder joint stress and stronger, more solid lifts.