Ive been coughing lately and my chest well i dont know if its my chest its above my stomach it seems like its?

puffing out a lil and when i feel it its like muscle both sides are even tho is this part of puberty or what? its like above my stomach its like getting a lil bigger then usual

its not my lungs for sure. Its either im doing too many crutches or its something else cuz in school i do like 30 crutches each day its muscle i think so anyone know if this is normal?