Are you running a stock kernel?? I too have this charger, some kernels ran hot. And some gave no notification while charging. The one that is working for me right is the Chaos 8.1. Hope that helps.
It may or may not be the charger.
Re: Headphones for nexus 5
I was thinking about getting a pair of nokia purity, are they still working after the 4.4.2 ota?? I saw someone say they were using them.