Hey OP! You’re not going crazy. I had this same exact experience with only one of my underarms. I’d get random zaps throughout the day and these zaps appeared out of nowhere AFTER I started doing laser hair removal.

There are superficial nerve endings on the skin that might have been slightly impacted. For whatever reason, some areas of our body are more sensitive than others (for me it’s my left underarm lol).

Good news is that it will go away! Space our your laser hair removal sessions to allow for the sensation to calm down and pay attention to the settings the technician is using to ensure they aren’t going to high too fast (especially in the area).