iPod doesn't charge?

I've owned my iPod touch 4th generation (8gb) for a little more than two years. Recently while I was using my computer (a MacBook 2008) and it was plugged in a warning popped up on my computer saying something about how the "USB was draining to much power from the computer and should be unplugged." So I unplugged my iPod, and then tried plugging it into a wall outlet, which at first seemed to work, but when I came back later, there was a warning on the iPod saying that "charging was not supported by this assessory." Now I find that it is impossible to charge my iPod anywhere.

Is there something wrong with the battery? Should I get it repaired? Or has this one's time come, and is it time for a new iPod?