my phone only charges when its off? and it only charges until it turns on

I have an iphone 4, I woke up one day picked up my phone from the dock and notice it did not charge, I tryied using my computer and it wouldn't work eather, then the next day it work it charged completly came home try to use Itunes and it would not read my Iphone. and again it does not charge while its on, it only charges when its off. I tryied my car charger, my computer and 2 diferent wall units, none work. Can you please explain a posible solution. Thank you