Thatís NOT good. I have heard of this happening on phones before, heating on the earpiece area of the phone that is. I have not seen it on the S4 yet though. I want to ask you some questions that might help to solve this issue.
When did you get the phone?
When did this issue start happening?
Have you downloaded any applications recently?
Who is your service provider?
Usually not a good thingÖ there is a chance that your phone might be heating up because something(s) running on the unit, something that the phone doesnít like.
If this issue happens often then I recommend you try and remove some applications from the phone, with a last resort being a Factory Data Reset
. If a factory data reset doesnít work then check for liquid or physical damage and try to file a warranty claim.
You donít want your phone to heat up and damage itself causing even more issues. Good luck Mike. I have the S4 too! You chose an AWSOME phone but you might have gotten one of those 1/100000 defective lemons.