Are you running the stock firmware? Do you have any third party apps installed?
If the phone is completely stock and is burning your ear, you need to return it.
My first Captivate was overheating and draining the battery (stock) - The 2nd phone didn't get hot after an hour long voicecall, my 3rd captivate got hot (stock), and now I'm on my 4th phone - I tested the phone at AT&T - after 8 minutes, the temp was warm, but not HOT - I did some app installs over the weekend, did a firmware flash, and noticed the phone was getting hot again.. I reflashed the firmware to stock last night - Charged the phone fully overnight - After a 10min call this morning, the phone was not hot.
So, not sure if a third party app or flashing the firmware has caused this problem or not, but it seems to have been fixed (at least this morning) by going back to a bare phone
Current apps installed:
Facebook / Launcher Pro / Home Switcher/ ATK
I can update later today once I'm on a voice call for longer than 5 minutes - I have another post on here about Voice calls and battery temperature and it shows my log of the temperature after so many minutes.
But it does only happen when the voice call is going through the ear piece - if speakerphone is on, it does not reach high temperatures
Also - I have turned the phone off after the batter widget/app showed 117 degrees, and removed the battery - The battery itself did not feel as hot as the phone did near the ear piece..