This happeened to me on the way into my work today. It has to do with the charging cable.. either losing connection or an issue with the cable in general. Keep in mine the LIghtning cables are under warranty for 1 year as is the iPhone. If your within that period Apple will swap out the cable. I've found that even when the Lightning cable looks and appears fine, like mine in my vehicle, it can and will still cause issues. My iPhone literally beeped at me like 3-5 times today during my commute. Good luck. The next cable(s) I invest in will be a 3rd party cable. Also, Apple offers a micro USB to Lightning cable adapter, which I do own and has worked out awesome. It is too bad VZW doesn't sell it.
3rd Party VZW Lightning cable: http://www.verizonwireless.com/accessories/travel-charger-for-apple-lightning/
Apple Micro USB to Lightning connector: http://www.apple.com/shop/product/MD820AM/A/lightning-to-micro-usb-adapter?fnode=97
This espeically comes in handy if you have a good bit of Micro USB chargers in your household as I do.