Why won't my iPod charge?

I always have to keep getting new chargers like every month and a half. My charger was working fine like an hour ago, but now it won't charge. Every time I plug in my charger the battery life symbol goes from red to white to back to red again. Or from the small white it's on, from when I restarted my iPod to a bigger white to back to small again, in a second. I plugged the USB cord into my laptop, it does the same. I plugged it in another outlet, it does the same. I used a different cord (old one that still worked) it does the same. I used a different white thingy you plug the usb cable into. I cleaned the inside of my iPod charger port. Idk what else to do. The cable I have now is in great condition still and i've have it for like a month and a half now. I had my iPod for like 3 years now. I haven't dropped it that much, it was always in it's outer box when it dropped a little. It's not damaged or cracked, no scratches, still in great condition like almost new. So idk if I just have to keep getting new chargers, or if there's something wrong with my iPod battery :c