One of the best things I can tell you to do in regards to heating up is make sure your data connection is turned off or your hooked into WiFi. Cellular data can cause the phone to heat up fairly quickly because it requires more processing power than a WiFi connection does. Also, make sure you don't have any apps running in the background that shouldn't be. Best way to do that, if you want to "close" an app....always make sure to use the back button at the bottom of the screen. That tells the system that you are done with it and when it needs to reallocate resources the app will be closed.