Heating issue with Samsung Galaxy S4 mobile

Hi all,
I purchased a new Samsung s4 it is fabulous and having very good feature in it and it have a good battery backup , but i got a heating problem with this phone , i don't know basically what the problem is ? Anyone know how to face it please reply
becoz i don't understand it.

Heating problem with S4, I have never heard this before.. are you facing problem while talking for long or facing this problem when you are playing games etc. ? Do you get your phone heated up when you are charging it ?