So I was thinking if someone has a song stuck in their head when there is no outside slurce of music that does not mean they are schizophrenic as long as they know there is not an outside source of music

But if there is no outside source of music and they believe there is an outsude source of music then that is not just a hallucination but a delusion and might indicate schizophrenia or schizotypal or psychosis

What do you think can you have a song stuck in your head without geing mentally ill?