My iPhone 4 stopped charging and won't charge anymore, any ideas???

I was charging it and listening to pandora when my phone started to feel really hot! I couldn't really touch it. The USB port that plugs into the outlet was hot, along with the actual USB plug in. And then the plug that goes into the phone was very hot too, and the bottom of the phone where the charger goes in was hot. So, in long story short, everything was hot. That was the first time I experienced that, and it scared me so I quickly unplugged the cord and it started to cool down. Not it is completely cooled, the phone, and the cord, and when I try to plug it in again to charge it doesn't charge. I thought maybe it was just the cord. So I got a different one, and it still didn't work. I even tried plugging it into the computer, and still no luck.

Some additional information, I was using an extension cord, and was laying in bed. I also have been experiencing issues where the phone would be plugged in, and say that 'it is not supported' or something like that, and would stop charging. And also earlier today I upgraded my phone system to the 6.1.3

Please help!!!!! Will I have to send it in? I hope my phone isn't completely dead! :(