Weird things happening. Help!

So it charges and says so when its dead and then the apple logo goes up, then the ipod goes to lock screen and says it's not charging from there, and it doesn't and ends up dying quickly. If I leave it alone and plugged in it will be dead, then the apple, then lockscreen, then die and repeats. And iTunes doesn't recognize it when plugged in so I can't back anything up. Also it's a brand new charger so it's not that.

Help??