I've been getting the tingling and electric shocks sensation for a couple of weeks now. The start of it coincided with a doctor's visit allaying my fears about heart fluttering - the heart issues stopped almost immediately, and the head issues started. I've noticed that I feel much better when I'm doing something - for a couple of days after I went back to school, I felt almost completely normal. It's when I'm alone with my thoughts that I start feeling things. I'm not on any medication, so I'm guessing (hoping) it's the anxiety itself.
The one thing that is weird is that the tingling feeling is sometimes pretty enduring. I felt tingling on the side of my head and left cheek for close to a week almost non-stop. But again, I noticed that sometimes I would wake up feeling completely normal, then start in on "Do I feel it? No... am I sure? wait - there it comes. Just a little. Is that it? Yup..." as if I was making myself start feeling it again.