why wont my ipod play certain songs even though i can select the song

i go to artists, the artist is selectable. i go into their albums, the album is selectable. i select a song from the entire album of songs that is also selectable, and the song skips to the next one without playing and then the entire album does the same. one song after another the whole album is run through within a matter of about two seconds. how do i get the songs to be able to be played on my ipod classic, i have an ipod touch as well and it doesnt have a problem with the same songs so its not the files. the songs also play on my itunes and it says theyre on the ipod, but they dont (refuse) to play.