I call myself a freak of nature because of so many strange or rare things go wrong in my body. Here’s one about my Vagus Nerve. For more than three years, I get hiccups 10, 15 sometimes 20 a day. I asked a number of my doctors why this it was happening. I would have gotten more answers from my bedroom wall had I asked it, so I started to research the answer. I said huh, when I found it. It seems that the Vagus nerve, carries the signal for us to breathe. Guess what nerve is right next to it, the nerve to make us hiccup. Now here’s the weird part, when the signal to breathe changes, like when you’re waking up, the change causes the hiccup nerve to activate and I’d start to hiccup. It seems the hiccup nerve can activate anytime your breathing slows lower than the the hiccup pulse and Bingo, I have hiccups day and night. Strange things can sure screw up your life huh?

Actually, your doctor was correct - It CAN make people pass out.

The vagus nerve, which is what you're stimulating in your neck, can cause fainting. For example, if you had blood drawn and you get dizzy, its vagovagal response/syncope, which is because your system will be triggered and cause your heart rate to slow to the point you pass out.