I have severe pain on my right shoulder. it hurts when breathing or moving. it is on the top of my shoulder, where it rotates. what could this be?

Many possibilities: With your description of pain at your age, there are many possibilities of a pain source. It could be as simple as an inflamed shoulder or neck problems. But it could also be something like lung problems, liver problems, gallbladder problems. Since there are so many possibilities, we would recommend seeing your primary care provider to help direct your treatment!

AC joint arthritis: If the pain is at the top part of shoulder, especially when you push on the one, you could have some arthritis at the small joint at the end of your collar bone (ac joint). If it is more at the ball of the shoulder then at your age, it can be a labral tear. You can also have a rotator cuff tendinitis. I wold get it checked out by an ortho specialist.