Re: how to solve lumia getting hot problem?
There are technically three options.
Soft reset -> hold volume down and power button until phone vibrates and restarts. No data erased.
Hard reset -> Settings -> About -> reset phone. Wipes phone completely. Be sure to back up.
Lumia Recovery Tool ->
How can I recover/reset/restore my phone software? - Microsoft - USA
Follow the instructions.
Lastly. Using data heats up the phone. Playing games heats up the phone. Using the GPS for driving directions heats up the phone.
This is the same for all phones. If your phone is getting excessively hot then I'd suggest using the Lumia Reovery Tool. You have a bad update installed.