What Causes Popping Sound In Chest With Pain During An Injury?

So i was on a toy at a park and i had fallen and i landed on my chest i heard a pop. i couldnt breathe for a couple seconds. But after, i wasnt in pain anymore i got back to what i was doing it was painful when i coughed or tried stretchin. That had happened about 2 days ago and the pain has dimmed down.