Have you been tested for Lymes Disease? Thats the first thing that sprang to mind when I read this post as I've read people explaining electric shock sensations on here before and then going on to be diagnosed with Lymes. Lymes can also cause migraines and other weird symptoms I believe. Its caused by an insect bite.
I am no expert but it may be worth you doing some research and asking to be tested. I know that Lymes is often overlooked in diagnosis.
There have been people on here that have Lymes in the past maybe one of them can offer you more information.
I hope you get some answers soon!