iPhone XR getting hot since latest software update

Hello,

I have been using my iPhone XR for some time now but since the latest software update I find that when I use it, it gets warm, sometimes too hot to hold at the bottom of the phone.

It is fine when charging, only when using. It cools down quickly when i dont use it.

Why would this be? Is there a fix? A software update to fix it?

I have tried all the online tips I could find and I have no pending app updates either.

A tad irritating...

Please help...

Thanks