@S K Singh: When using power intensive apps, you may notice that your device heats up due to the strain that the app places on the operating system. This is normal, however it should not reach a stage where the device becomes too hot to handle or uncomfortable to hold. If the phone overheats beyond a certain temperature, a warning notification will appear on screen, and the phone may shut down as a precaution to allow it to cool. If this doesn't happen, then you don't need to worry. For further information, please take a look at the link below.
https://www.samsung.com/uk/support/mobile-devices/what-to-do-when-your-phone-heats-up/
