I've developed a few in my armpits, and under area bra is over.
I've read and heard, they are not due to weight gain or diabetes, but can commonly occur in areas where something rubs against,sweat gland areas and heredity.
I just started getting them,I'm 50, and I've been linking them to aging and excessive sweating from the damn, hot flashes.
I need to eventualy have them removed, they get snagged when I shave. Hubby had a few on his face, and were "burnt" off with cauterization, he felt hardly any discomfort. There are different techniques of removal, I guess it depends on which one your doc uses and possibly location and/or size of the tag(s).
Lots of luck on what you decide to do with them.
My gram had them and when we were little kids, they referred to them as "bread crumbs", but to me "tags" make more sense.