What a good pec workout?

dumbbell flies, chest presses, and push ups are probably the best and safest, but when doing dumbbell flies you need to make sure never to straighten your elbows when you open up. I would suggest drinking anything that has a good amount of carbohydrates before a workout, but do not drink too much. If you fill your stomach before exercise, blood goes to your muscles in place of digestive organs, and you risk throwing up later on.