30gb 5.5 gen video won't play music

One day I was listening to my iPod, and the audio suddenly got really screechy for a minute or two, then stopped completely. Now it doesn't play music through the headphone jack nor the dock connector. However, everything else works fine. It charges and syncs with my computer fine; also, when I select songs to play on my iPod in iTunes, they play just fine. Any ideas?