I was outside installing a light fixture yesterday and just shut the switch off, not the Breaker. There's only myself and my GF here so I knew I would be safe. Especially after my warning to her..
"Don't turn on the switch"
"The switch for the light you're working on?"
"Ya...But just in case, dont touch any switch in the house until I say so"
While I was working on it, I grabbed a wire and twisted it in an awkward way. Something in my hand popped and sent a pain right up to my shoulder. I've been shocked by 120Vac before and it felt the same. I actually had to go check the switch again to make sure it was off and it was. Weird.