The problem is that many gym rats have strong front deltoids from all the Bench Pressing over the years. Although the Bench Press is a great exercise for overall front shoulder strength, it may at some point pull your upper body forwards if the upper body is not developed in balance, and any asymmetries are not addressed.
Use the following exercises to build stronger and more resistant shoulders.
EXERCISE 1: Lateral Raises
Do this exercise without any momentum. If you see that this is not possible for you while standing, take a seat.
The weight will start at your sides, not in front of your body, to prevent you from using your back to cheat the motion. Control the tempo as you raise the weight. Pause at the top and descend slowly. Imagine the Dumbbells are each a glass of water that you want to spill slowly.