When you sleep on your back, your pillow lets your head drop forward. Your neck angle shifts. The soft tissue at the back of your throat collapses inward — and the airway narrows.
Air forces through a smaller opening at higher speed. That turbulence makes the tissue vibrate. That vibration is the snoring — and the first signal your body is starving for air.
It doesn't happen because of your weight. Not your age. Not your genes.
It happens every night your neck isn't held in the right position. Fix the position and the airway stays open.