What Causes Breathlessness And Chest Pain?

I am having shortness of breath and my chest Hurts. it s not constant and it happens in like 2 beats (like a heart beat. So i will be souring and fine and then it builds and beats hard 2ce.) .i had it about a year ago and went to the doc to have my heart checked and they said i have a really really healthy heart. i am thinking it could have something to do wroth my lungs?