iphone 5c damages the charger and the pc as i plug in – iphone , Assistance needed problem

hello
today i became an iphone 5c Along with charging problem. as i plug into the charger the led goes off and chager doesnt work until i plug out again. as i try to connect to pc, all usb connections goes dead on my pc and the pc says this device has too high voltage. i changed the dock flex but still same problem.
i hope someone can to be helped
thnx