The best exercise for working the upper chest is the Neck Press. The neck press is performed on a flat bench with a barbell or better yet a smith machine. Lie down on the bench with your feet up off the floor crossed. Knees pulled in toward chest. The reason for this is to keep the back neutral and to isolate the chest better without arching the back and using the legs, like power lifters do. Next, grab the bar with a normal bench press grip. I like using the smith machine best because I use a palm grip. The palm grip is when you position the palm of the hand on the bar for total bone support. This type of grip cannot be done with a free weight olympic bar because it will slip from your hand if you are not careful. It is best on a smith machine. With a palm grip I don't wrap my fingers around the bar. This takes the fingers out of the exercise. I find that if you wrap the fingers around the bar you will use too much of the forearm to lift the weight. Your hands and forearms will fatigue faster before the chest does. So, keep the finger open and use just the palms. Turn your elbows out so that the meaty part of your palm, base of thumb, is in contact with the bar. You want the elbows out wide to pre-stretch the pectorals. Now bring down the bar-slowly! Keep the elbows out wide the entire time. If the elbows go forward you will lose the engagement of the contraction and you won't be using the pectorals. You will use the triceps and the anterior deltoids. Keep the elbows back. You will get a tremendous stretch in the pecs. Bring the bar all the way down to the neck. Above the sternoclavicular junction. Hold for 2-3 seconds then push the bar up slowly, keeping the elbows out. This is the best upper pec exercise I know.
The Smith Machine.
There are many so called experts out there that say the smith machine is a useless machine. That we should not be performing artificial stabilization or constricted movements to build muscle. This is ridiculous to me. There are many great exercises that you can perform with a smith machine that are safe and produce great results. The Neck Press is one of them. I have been performing the Neck press for over 20 years and have never gotten injured or had any ill effect on my physique. It only has improved my physique. Give it a try I am sure you will like it.