The floor press isn’t just a simplified version of the bench press that you can use when you don’t have access to a bench. It’s an exercise with a few crucial changes from its more well-known counterpart that you should consider, especially if you have a shoulder issue.
Because the range of motion in the exercise ends at the floor, the floor press puts less strain on your shoulders than the bench press. Because you don’t get the same assistance from your legs as you do with the bench press, lying on the floor puts additional strain on your upper body.