Device heating up as soon as i switch on
A little bit heating may not be an issue thought it should not have happened.
Keeping it on soft surface like Bed may cause it to heat up.
Do not cover your device inside any non-insulator material.
Hope this information is useful for you
Its okay, even my device heated up when i was using.
Hardwares do produce heat, but try to keep it cool, either use a computer fan or use any other fan.
if you have a thermal scanner camera it might be possible to check if there is a over heating issue with any component in the device so that it can be fixed if necessary.