Iphone 4G troubles. Won't charge and computer won't recognize it.?

I plugged my Iphone4 into the USB and it will not connect to my charger or computer. Therefore it won't charge. I turned my phone off and it is showing that it needs to be charged but is not recognized by my computer and won't charge via wall charger. Yes, I have tried different cables and still no luck. If anyone has any great ideas to fix it, I would love to hear it so my phone can be fixed. Thanks.