I am 57 but active physically and am slim weighing 65kgs for my height of 5'7. I used to jog about a couple of years back. When I exert myself by running for short distances i experience a slight pain in my chest when breathing but it stops after some time. Laos when i jog regularly the pain does not appear. I suffer from mild asthma for which i take an inhaler. I do not have hyper tension nor diabetes and am healthy otherwise. I do crunches daily for my stomach and push ups to keep my chest and arms toned. I take part in adventure sport activities. Why does the pain appear then disappear? do i need to check my lungs or is there any vascular problem?