I get this now on a regular basis. Mine has not been as painful as it is annoying and very ODD! Sorry you have pain form this.
I also get pressure and that tingling/pins and needles feeling in those same areas and down my inner thighs when I have to go to the bathroom for 1 or 2. I dont get the normal feeling of needing to use the bathroom anymore.
I am still in limbo land and waiting for another MRI. Going to tell my dr about this on Monday.
Oh we have discussed this before. Electrical jolts, and vibrations - all without the benefit of batteries - can and do occur in the areas you referenced.
If this continues you really will need to call your neuro's office, if it's a male and you're too embarassed, talk to the nurse, but please remember the doctors have heard all this before and your story won't come as a shock to them!
Here's hoping the shocks quiet soon. It's no fun - been there, done that.
Lulu