iPhone 11 overheating for no reason

It is not clear here in your post about the ambient temperature in your area where you are using the iPhone. However --> Keeping iPhone, iPad, and iPod touch within acceptable ...

Store the device where the temperature is between -20º and 45º C (-4º to 113º F). Don’t leave the device in your car, because temperatures in parked cars can exceed this range.

Use iOS devices where the ambient temperature is between 0º and 35º C (32º to 95º F). Low- or high-temperature conditions might cause the device to change its behavior to regulate its temperature. Using an iOS device in very cold conditions outside of its operating range might temporarily shorten battery life and could cause the device to turn off. Battery life will return to normal when you bring the device back to higher ambient temperatures. Using an iOS device in very hot conditions can permanently shorten battery life.

Your iPhone should not get too hot to touch. It is OK if the iPhone gets warm once in a while however it should not get too hot to touch.

Try and Force Restart your iPhone exactly as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears then release the Side button (Can take up to 20 seconds. DO NOT release Side Button when invited to Slide Power OFF).  

If the above does not work and your iPhone still continues to get hot then take advantage of your Apple 1YR Limited Warranty (US) and have it examined at the Apple Store or at the Apple Authorized Service Center. If they are not open in your area then please contact ➔ Apple Support

Axel F.

You are welcome.

Axel F.