iPhone 7 Plus Camera Issues

Hi,

For a few months now my iPhone 7 plus camera has had these issues, however recently it is constant. When open my phones camera - or any other app that uses the camera, e.g. snapchat - the camera constantly freezes and either the screen turns green, pink or black. A temperature warning pops up (although phone is not hot) for a few minutes and won't allow me to use the phone at all. After that I get a warning message in the camera saying the phone flash is disabled due to temperature issues.

I've reset everything I could, including completely clearing my phone. Operating system is also up to date. However the issue is still there. Does anybody have any clue what the problem could be?

Thanks!