Often, but never seriously.
Yes and it sux.
My pride's been sucker punched a number of times, but only one physical injury...I stuck a pick through my hand when I was working for a cable harness manufacturing place.
Yes - working as a Residential Social Worker it's an occupational hazard ; I once got a split lip and on another occasion a broken thumb.
Yes. I fell once on the matrress I keep strapped around my back