When I play certain overtones and/or altissimo notes the area behind my ears, the front part of my head, and another area in my forehead feels like it's being electrocuted or punched. I mean the 'electrocuted' part literally and do actually have something to compare it to (I caught my wet head in a bare wire when I was approx. 24 years old). It feels like if I hold the note for long I'll fall or pass out. Is this normal? Have I found the coveted 'brown note'?