If you have used the phone at a stretch for more than 150 200 hours without any restart this may lead to overheating. It does not seem to heat up noticeably during charging though.

Users Are Reporting That Some Google Pixel 3s Are Overheating
Pixel 3 heating up. Keep your pixel 3 xl from heating up. It turns off when it gets over heated so i thought thats what happened. A message pops up on the screen of the google pixel 3 informing the phone owners about the phone turning off because of the temperature. The problem is affecting both pixel 3 and pixel 3 xl and can cause them to shut down. My phone turned off about 12 hours ago. At the upper right side you will find three lines.
If you see no command text all you need to do is press hold the power button and press volume up button one time. My pixel 3 is shutting down without doing anything at all. To check the update for apps in the play store. First of all keep in mind that your phone warms up when its plugged in. Go to google play store. Google pixel wont stay on and keeps overheating.
If you have recently bought google pixel or pixel xl no doubt you are the one to hold one of the most impressive smartphones in the market wrapped up with high end hardware specifications and great design. Now go through the apps and see if any latest update is available or not. Some google pixel 3 smartphones are experiencing overheating issues while charging andor video calling. Google pixel overheating issues bother quite a few owners. Typically speaking charging of any kind can cause your phone to run more on the warm side but these pixel 3 overheating reports are certainly a cause for concern. Power off your google pixel completely.
Ways to keep your phone from heating up. Now press volume down 2 times and then press power button to open recovery mode. My partner recently bought a p3 and has had it die 10 min into a whatsapp video call due to heat. Pause resource intensive features or apps until your phone cools down. If your phone is too hot to touch use a different phone tablet or computer to contact pixel support or nexus support. Then tap update all.
Apparently when the device is. View entire discussion 22 comments more posts from the googlepixel community. But despite all these things this device is not bug free and users have complained of several issues. Keep your phone away from direct heat or excessive sunlight. Press and hold power and volume down buttons altogether until the phone boots into fastboot mode. Therefore dont ever keep it charging more than needed.
It stays on for max a couple of minutes. The phone overheats while it is connected to a charger while using the camera application or while using an application like whatsapp for 10 15 minutes. Go to my apps games.