Chest pain when running, worse with breathing and applying pressure?

I'm am 16 year old male, not overweight, average build, don't smoke, and for the past few years, I've noticed that when I run for a matter of only a minute or so, I get this chest pain in my upper chest and throat, and it really hurts to breathe. It's like a burning which really intensifies when I take a breath, and my chest also becomes tender and hurts a lot if I apply a little pressure to it.

I've been to the doctor concerning my heart before, and he listened to my heart and lungs, did my blood pressure, blood oxygen levels, pulse, BMI, lung capacity and things and they all came back fine.

I was just wondering, is this something to do with my breathing? I tend to breath in a lot through my mouth, and I've heard mouth breathing can cause this, so if anyone has had any experience of this, or know how to make it better, I would be very grateful.

Thanks in advance. :)

[Dr San Miguel]

Hi. Has your doctor ruled out exercise-induced bronchospasm (EIB)? EIB happens when the airways in the lungs shrink within 15 to 30 minutes of nonstop exercise. EIB might be caused by breathing air that is cooler and drier than the air in your lungs. Symptoms get worse during cold weather, spring or fall. Warming up for 15 minutes before you start exercising may help prevent attacks. Always breathe through your nose while you work out because that helps warm the air that goes into your lungs. For further advice, consult your doctor. Hope this answers your question.