Chest pain and breathing difficulty while running hard.?

I think you should go visit your doctor to see if you are diagnosed with asthma. Asthma is an inflammatory disorder of the airways, which causes attacks of wheezing, shortness of breath, chest tightness, and coughing. If you get these symptoms that go along with the definition of asthma then you might indeed have it. Asthma is something you can cure, so don't worry. Just take time to get lot's of rest and drink lot's of water so that you won't end up with a more serious condition. Just check in with your doctor and hopefully everything will go great! Good luck :).