Hi Mark and thank you for your reply.

Dr mentioned that sleep apnea is often seen in obese people but because I'm not overweight this, if I do have sleep apnea, is not the cause (??)

How did your shaking feel just before falling asleep?

Mine always happens as I'm almost asleep, and it feels like the nerves or something shaking inside of me. Was your shaking visible or just felt like it's inside you?