Hi Saranya, I really like your name!
Yes it can be very embarrassing can't it? A few friends have seen me do that too and they frown and say "what was that?" But sometimes it just looks like I was shaking my hair back. I asked my husband if he saw it a few times and he says yes but he doesn't know that it's not voluntary unless it pulls my arms too. I usually feel it coming on and can sometimes prevent it by bearing down somehow.
Basically my muscles are just way too tense and my neck is injured. The chiropractor said it's like a 6 lane highway squeezed through one lane. So the signal from my motor cortex isn't getting through properly. I have other problems like not regulating my body temperature and compensating for changing position so my blood drains from my head and heart down to my legs (called POTS) and about 10 other things. It's all called dysautonomia.
Stress is not the cause but makes it much worse. It is always at it's worst when I lie down.
I really think this is another symptom of my dyfunctional nervous system that is inherited and worsened with my head and neck injuries.
I hope you can find something to stop it. I hope I can too. I've only had this a couple months. It's my newest symptom.
Oh something else I do - often just before I twitch, I lightly gasp. Anyone else do that?
Did either of you find out what the cause of the involuntary muscle contractions was? It could be caused by a low level of blood calcium which is involved in muscle action.