I used to feel that when i was running, beggining to run then, and it went away over time. But i can't say it was my lungs that hurt, but the sides of my ribs. You know, the muscle area.
Couldn't have described it better. Something tells me it has something to do with bloating since every time it happens to me I start to burp and then I feel relief for a few seconds and then it starts again and again, but that's just me.