This is an unfortunate complaint, and I am glad that you have already discussed this with a physician and had various tests done. Whenever a person is having chest pain, that person needs to speak with a physician in person rather than via the internet, as it could be a life threatening emergency.
In general, the first thing that doctors worry
about with chest pain is anything to do with your heart, such as a heart attack. Since you are so young and sound active, that is, of course, less likely. Even so, I am glad you have spoken with your local physician. A more likely cause of your pain would be something musculoskeletal, such as costochondritis. Musculoskeletal pain can be sharp and stabbing as you describe, and can be made worse with pressure (by pushing at the affected spot) or movement. If the pain generally occurs in exactly the same area, costochondritis is even more likely. Costochondritis is the name doctors use to describe inflammation of the joint between your ribs and your sternum. It is common, even in the young, and generally improves with non steroidal anti-inflammatory drugs that you can get over the counter. Again, please speak to your doctor
to make sure that you are being treated correctly and have the right diagnosis. Chest pain is very serious and should be treated accordingly.