I fell backwards yesterday from a frisky chair with rollers onto a tile floor and hurt myself. Luckily I didn’t hit my head. My neck must had twisted and I landed on my hip, behind, back and thigh instead.

My iWatch is alerting me all day I’m in tachycardia. My PM is supposed to pace me down to a steady 70. But it is not.

Is my tachycardia from a pinch neck nerve?

You didn't say what your heart rate is and whether it's sustained or comes and goes or what. Never mind the watch. Use your Kardia.

Neck strain was always an afib trigger for me, so not suprising a fall like that put you in tachycardia. Many possible reasons including vagal nerve stimulation, and yes, a compressed nerve as you suggested.

Jim