My boyfriend is getting this random sharp pain in his chest. Its not where his heart is. We dont know if it's his chestplate, lungs, or what. It just comes very quickly and suddenly. It's right in the middle of his chest. He says it's like a spike being stabbed in there and the pain stays in on spot while it's dull throughout he rest of his chest. He's yawning after every time he gets the pain. Please tell me what it is and what to do. And once again, it's not his heart. Thank you! He's 17, 6'3 a healthy weight and he does run parkour. If that could change it with straining or stressing or anything. thank you!