Healthy teenager that exorcises a lot has chest pain in center of chest?

Lately like this last week ive been having chest and back pain. The pain in my chest is in the center in between my breasts then just below also. Its also in my upper back. I have a sore throat but no coughing. Im a swimmer so i work out a lot and im in my healthy range for my age and height. I don't know whats wrong and I don't want to tell my mum because she'll think that nothings wrong. She always tells me I complain a lot even though i really don't. I tell her stuff once its been happening for a while. You have any idea what could be causing this?