IPHONE 5 weird screen responses when plugged in

I noticed recently my IPHONE 5 6.0.2 has started to act weird when plugged in, I am on my third iphone 5, Returned the other two firstly becaue of battery issues and then wifi issues now its crazy when plugged in. It is as if the touch screen has become electrified...if i am typing a message on the keyboard it will randomly go back to messages, or jump to the edit screeen. If i am on the home screen i have to touch apps like three or 4 times to get them to open. It only happens when the phone is plugged in. I am using the cable and plug that came with it plugged into the wall socket. Hang on to i test plugged into my computer.,......same even more spastic if that was possible whaaaa whaaaaa whaaaaayyyyyy is this happening to me!!!!!