I have my S4 for about 6 months now. It overheats when I talk more than 10 mins, and when GPS is on, so navigation will be annoying and have to cool it down with AC to avoid it shut down. Then the screen freezes, the keypad freezes and it's being very disruptive. The worse thing is the battery so I miss half a day sometimes if no plug is around or without a portable charger. Before this, I had a S3 and it was perfect. I wish I have never upgraded...Any help or sggestions? I went to a VW store and they told me to uninstall Viber?
Are your apps up to date? How much do you have running in the background? Any LTE/Data network heavy services?
I would use an app called CPU-Z and throw it into multi-window mode to see if any particular app causes the CPU usage and all clock speeds of the cores to spike up drastically. Also, if you have any games that are sent to the background (home button) rather than closed (back button), this may be a drain on the battery.
Also, if you have any task killers installed, please remove them.