what exercise builds the upper chest
Build the Upper Chest with the Flat Bench Press. You will certainly find the upper and lower difference for the chest legitimate, but emphasizing each part through different exercises is misguided. The flat barbell bench press ranks as the safest option. Use this to continually overload the upper chest. Use more weight, in good form, as you grow stronger.
Bone structure is key to upper chest development, so some people are born with an advantage. However, anybody can improve their upper chest area with specific exercises, such as incline-chest presses. Most people can't bench as much in the incline position as in the flat position. But don't let that get in the way of your goals. To build your upper chest fast, do a specific workout twice a week.