Currently Being ModeratedJan 2, 2013 5:15 PM (in response to eliran 23)
Probably a defective charger that has some switching noise leakage to the USB output. From there it goes via the cable to the phone. With no case of the phone, it goes from the metal back or sides of the phone to your hands. The signal on you hands then causes errors in the touch sensing.
Try a different charger.
Currently Being ModeratedJan 3, 2013 12:50 AM (in response to Malcolm J. Rayfield)
I also tried with another charger, same thing.
It happens to more people not just me.
Currently Being ModeratedApr 2, 2013 10:33 AM (in response to eliran 23)
I also have the same my iPhone 5 screen starts to jitter sometimes when I connect it to charger and when I holds the screen with any sort of scrolling on it(except on home screen) but new thing thing that I noticed is that it stops to jitter or sops o show that strange behaviour when I charge it without phone cover ( silicon cover purchased from a local shop) and except that every thing is original i.e. it shows only when it connected to charger with cover on it. Just try charging your phone without phone cover on it and tell me wether it jitters or not