Overheating phone

Yes, it's normal, as per this support article:--> If your iPhone or iPad gets too hot or too cold

If you still think it's overheating, for your peace of mind I suggest that you make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> https://locate.apple.com/choose-country-region . After checking it out, they'll give you all the available options.

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.

We, just users like you, cannot diagnose that kind of issue remotely, sorry.

That's why I suggested that you, to feel more comfortable, have your device inspected.

Regards

Giulio

My pleasure