I heard my type of shyness described as paralyzing and it felt like the best description I’d ever heard.
In a social setting you’re mind kind of freezes; certainly it works in a way that is totally contrary to how you would like it to work. For example, instead of speaking about something, the mind tells you to stay quiet or to change the subject. So later you kick yourself for not having expressed yourself as you would have liked to. And this type of behavior goes on and on. So, I would add another “P” word: persistent. And yet another, painful.
Painful, persistent, paralyzing shyness.