What just happened, scareehhh?

I was at my cousins and they have a slick half-pipe, and i was wearing socks and I fell from the top and I hit my back weird and it still hurts(a few minutes later) and I couldn't breathe right for like 2 ,ins i could only take in gasps of air or breathe out and my upper back hurt so bad that i wouldn't let go of it for like 3 mins and my stupid little brother(8, almost 9) said "Oh you can breathe, youre talking" I would have puched him in the face, but you know, i was holding my back with both hands, anyways, i can breathe fine now but i want to know what i did and if it was serious,, THX :3