Why is my iPod Touch 4G switching the charging symbol?

My iPod touch 4g is about a year and 4 months old on the fourteenth of June. My original apple charger was breaking and it couldn't change the iPod normally because it kept flashing back and forth on the charging symbol. One minute it would saying charging and the next it wouldn't be charging but it's plugged in. So I got rid of that charger a few days ago. Now I have a charger that's new never has been used. It fits my iPod and everything but it is starting to do the same thing as before. Last night I noticed it kept switching every second to the charging icon to the regular battery icon while it was plugged in. I'm starting to think it is my iPod but this has never happened before until I started charging on my mothers laptop. I'm not allowed to charge on my betters Xbox 360 because it supposedly lags the games. Whatever. I just need to know why does it keep switching and not charging and how can I fix it so it can charge while its plugged in. Thank you!