Iphone 6 will not charge with factor cable charger

I have a iphone 6 just over a year old (go figure). I am using the factory cable and factory charger. Currently it will not charge, It has been acting up over the last few months, that is I had to unplug and replug to get it too charge. Now no mater what I do it will not charge. If I turn off the phone and plug in the cable either to the charger or the USB on my puter it will turn the phone on, but not charge the phone. Again this is the factory cable and charger and the cable and charge works with no problems on my freinds identical Iphone 6 bought at the same time. I have tried another factor cable and a aftermarket cable just in case but it makes no difference with my phone.