Sounds like a nerve problem to me. That diagnosis would be consistent with the burning quality of the pain, the location, and the fact that tucking your chin intensifies the pain (doing so applies more tension to the nervous system).

What did your physiotherapist have you doing? You said that it wasn’t much help?

If I’m correct and it is a nerve issue, chances are you’ll want to get a pro’s help, and probably a physio specifically. It could be a whole whack of things causing the nerve irritation, and without a proper diagnosis you’re just going to be shooting in the dark.