Hi there

I am wondering if you have had any nerve damage anywhere else? 

I remember seeing a news show about a condition where women were feeling this all of the time.  It became more than annoying to them...it was a chronic condition. 

I would try not using the vibrator for awhile to see what happens.  In the meantime here is what I found for you about this condition.

Here is one article addressing this issue.

And here is another article explaining Persistent Sexual Arousal Syndrome: 

"Spontaneous, intrusive, and unwanted genital arousal (e.g., tingling, throbbing, pulsating) in the absence of sexual interest and desire. Any awareness of subjective arousal is typically but not invariably unpleasant. The arousal is unrelieved by one or more orgasms and the feelings of arousal persist for hours or days." The panelists reported that this syndrome is poorly understood, but it may not be as rare as previously believed. This is a provisional definition offered to facilitate research into its prevalence and etiology."

If this continues...I would consult again with your doctor.  I hope you get some relief soon.  Thank you for your question.