I'm sure this is scary, but there are a number of things that could be causing this, from the not serious - a pinched nerve - to the more serious. It could be a nutritional deficiency, even.
You don't really describe if it feels muscular or not, but I'm including this, just in case - https://www.healthline.com/health/muscle-twitching#diagnosis
http://web.alsa.org/site/PageServer?pagename=ALSA_Ask_April2013 - this has an excellent explanation of fasciculations, or muscle twitching. It may help, even if what you are experiencing isn't exactly muscle twitching.
Let us know what the neuro says. When you go, have everything ready - a timeline as exact as you can be, a really good description of it, and if you can see it happening, some videos of it happening in case it doesn't happen in the office.