TsPoet sez: I think an earworm and an auditory hallucination must be 2 different things. So, being a scientist I looked up your claim and found things like this abstract:

From personal experience, they are very different things.

The earworm is an annoying snatch of song (my most recent one was a snatch of a hymn I dislike) that just worms its way into my mental conversation with myself. I find myself humming it throughout the day and it drives me NUTS. The worst, of course, is that I never quite remember the whole thing, so I just have a sappy phrase to put up with.

The auditory hallucination is a whole different beast. I'm starting to occasionally "hear" someone say my name. No I'm quite alone. No, it's not frightening. It is a bit weird, but I don't mind a little bit of weirdness in my life. In fact, I prefer this to that %*##@^!! hymn. Considerably less annoying.