Welcome to Android Central! What are you doing on the phone when it gets hot? Are you using any CPU-intensive apps (like games), or does it get hot even if you're just idling on the homescreen?
It starts getting hot as soon as the phone comes on like at the Moto screen. It's like hot to where I can't even touch it, right at the top where the phone speaker is.
I've heard of SD cards causing overheating, but not as soon as the phone is switched on. There's something badly, and possibly dangerously, wrong with the innards, is my guess.
belodion has a good idea -- if you have an SD card inserted, Unmount it (in Settings>Storage), remove it, then reboot. If the overheating stops, then card is probably corrupt.
If that doesn't help, then it could be a failing battery. Does the battery drain pretty quickly?