I've studied brainwaves a bit. And I have a sister who was the certified sleep study director in the state. The physical sensations imo are not from brainwaves. "Normal" stress might be the answer, as others have alluded to.. the tightness in the neck or even to the forehead... perhaps what you are sensing, physically, is from this. IMO the two experiences, though connected (stressors) and not one in the same. This is an interesting subject, and I look forward to the thread continuing...