iPod 5 charging problems

Well, my iPod stopped charging with my lightning cable.It wasn't a big deal so I just charged it on my dock. I noticed something weird while at a friends house. My iPod didn't work with his lightning cable either.Instead it did charge until my lockscreen appeared but after stopped charging.Then today my iPod didn't charge with the dock. I tried my lightning cable and that worked. I find it weird that this happened. When my iPod went completely black, I put it on the dock and it charged. It only charged for a few minutes until it turned on. What should I do?