Is my iphone 5 charger working?

Somehow when i put it to charge it won't charge, when i turn off my phone and put the charger on, it turns on. After its on it won't show the thunder symbol top right corner that is charging. What's happening?

Try cleaning the iphone dock and the cable with an old tooth brush. If that don't work try another usb cable. If that does not work try to do a battery reset. It could also be that your battery does not hold a charge any more.