Iphone 11 pro max keeps shutting off and restarting

So recently I did a back up to my cloud and during the back up process it stopped and never completed well I did a full factory reset on my iphone and then relogged into my apple id and it restored everything I once had but NOW it will randomly shut off as im using it and restarts and turns back on but any text messages I recently sent rant there nor show up anyone have this issue. So far I did a normal power off and restart than tried hard restart and I just reset the settings to factory and still no change please help