Pain in chest? please help?

aye im 14 nd i work out 5 times a week. i do arms and chest then the next day legs and abs and then i take a rest. Ok well i don't want a guesses here i want your best inference or something because i have this chain in the middle of my chest nd if i turn to the right or left it hurts at a scale of 8 out of 10. When im just sitting here it's about a 3-4. this has been going on for about 2 days and is very annoying. It kind of feels like a muscle pain, but what muscle is in the middle of my chest? it feels like it is inside my ribs. What is this?? if i just move my neck it's about a 6. help me :/