With a good bench press setup – upper back tight and shoulder blades creating a stable base to press from – your shoulders will internally rotate when the bar reaches the chest.
Lack of internal rotation in the shoulders, or upper body mobility in general, can be the reason for painful pressing. Working to increase internal rotation is one solution. Another solution is to work with and around the limitation by adjusting the grip/barbell type. The neutral grip bar allows more external rotation and will "open up" the shoulders.
- Use your regular bench press setup.
- The neutral grip position reduces the potential for torque creation, often called "breaking the bar." You have to focus more on upper back activation to keep the shoulders stable during the lift.
- For most people, a wide grip will be the least stressful on the shoulders.