Hi there, firstly, you are totally normal! Your head shaking/shivering/sensation thing is a symptom of social anxiety, clearly, not that I'm a professional or anything.
I haven't experienced that myself, although I get blushing and all the other common symptoms.
I know the sensations we experience when in social situations aren't pleasant, and I'm sorry you experience this :c Are you afraid that your sensation is noticeable to other people? It probably isn't
Anyway, you said you're not new to social anxiety - does that mean you've received treatment for it before? If you haven't, I strongly suggest you see a professional about it.
If you have received treatment before/are receiving treatment now, then I suggest you bring this symptom up with your therapist, because clearly it's the most distressing one.