I’m sorry that you’re having this difficulty, but I’m very glad that you wrote us here at Psych Central. Perhaps the best place to start is with the physical exam. As you list your age as 14, I would recommend you ask your parents to set up a meeting with your pediatrician. Here she will be in a good position to help determine what tests and which professionals may be best to help. There can be many reasons for what you are experiencing. A physical exam is a good place to start.
The fact that you are experiencing this discomfort and want to correct it is an important demonstration of your character. I appreciate the courage you have in writing us — now it is time to get a physical to get to the bottom of this.