Nice! It actually can be a bit tough, my highscore was 28. Good job on your second game, yet again, simple but fun. A great step forward!
As for music, there's tons of songs in the music section of Newgrounds (audio portal) that are labeled free to use with credit. Some people even make some that loop with the intention of them being grabbed and put in games. Might be worth a shot to search through for your next game!