See a Dr.

Dont screw around, dont look for home remedies, dont ask your friends what they would do, see a Dr.

Some things are beyond the scope of home remedies and suggestions, and if you are coughing up blood, and have that kind of pain from the blow, then its very possible that you are actually injured, and the only way to make certain nothing is permanently wrong is to see a Dr.

In the end its the best thing to do, because even if nothing is wrong, worst that happened was that you have to pay a Dr bill, but they can prescribe you some medicine to help with the pain if thats your thing. *wink wink*