Playlist doesn't resume where it left off.

When I play music on my ipod then close the music app and come back later, it doesn't start where it left off. So every time I want to listen to music I have to restart the playlist. It doesn't resume. I've already restored, rebooted and reset my iPod multiple times. Is there any way to fix this? I'd like to not have to resatrt a playlist after being 100 songs in.