If you are using iTunes to play your music be careful when adding music to the library. iTunes tries to be smart and by default it makes a copy of the music you have as well as tries to organise it the way it likes. So if you do not like your music organised by artist/album and so on it will render your music unsearchable. (This is true for me since I do not organise my music by the artist album and such.)
To save the whole lot of mess it creates set the following in your iTunes preferences .
This way iTunes will make a list of songs but not process them the way it likes. You can have your own organisation of music and save a lot of trouble for yourself.