I bench press and do other assorted chest muscle exercises consistently, every other day; however my left pec muscle is growing larger and stronger than my right. I am almost certain I am working them out identically, and when I push out on the bench, I push out evenly (without any weird movement that would produce a different effect). Does anyone know why this unequal growth is occurring?
That is odd. One thing you didn’t mention is if you’re using machines or not. That’s the downfall of machines in that one side of the body often compensates for the weakness of another side since it’s all connected.
Another thing to try is instead of using a bar or machines, use dumbells. This forces both sides to utilize equal strength to push up the weight. A barbell bench should be using both sides equally, though, but with dumbells there’s no doubting both sides are lifting equally.
Take a close look at your form to make sure you’re lifting correctly. Have an experienced trainer or lifter watch your lift to verify no mistakes are being made. Often it’s very difficult for the lifter to notice they are making a mistake but can be obvious to an observer.
As a sidenote, you shouldn’t be lifting the same muscle group every other day. You should allow at least three days recovery time between lifting the same muscle group, especially if the exercise is adequately intense. To lift too often risks overtraining and injury.