And how would have said device been inserted without you having any clue? and if you're sure its not a health problem why are you asking in a mental health forum about it...that seems to indicate you are at least considering the possibility it is health related. As far as I know though such technology does not quite exist yet even..though I don't work/study that field so I am not that knowledgeable on all the possibilities. But even if such a device that could cause some voice to yell at you does exist I doubt common criminals you'd end up having a few drinks with would have access to that kind of thing anyways.

Also though hallucinations wouldn't always point to any psychological issue or technological frequency thing anyways...even if you don't think its a health issue still might be good to consult some kind of health expert.