Well you may have Asthma like the other person says. I am not Doctor but you might want to have an xray of your Lungs. I have Bilateral Diaphragmatic Paralysis... Which means that both sides of my Diaphragm are paralysed... Now I could not run for 2 sec.s let alone 15 mins. But I do know you could have one side or the other.... You might want that looked at.. Good Luck!! Want more information just send me a message!! CT
Hello and hope you are doing well.
It could be Asthma, and it is usually triggered by allergens. There is an entity called exercise induced Asthma, here as the person starts exercise, the changes in the environmental air breathed in trigger an attack of asthma, causing cough and breathlessness. Have yourself evaluated for the same. This can be detected by a spirometry test.
Hope this helped and do keep us posted.