There is a lot of misunderstanding and fear regarding hearing voices , having visions etc.
According to the Hearing Voices Network (www.hearing-voices.org), somewhere between 3 and 10% of the people have experiences like these (increasing to about 75% if you include one off experiences like hearing someone call your name out loud).
It is possible to be a healthy, functional person and hear voices.
Schizophrenia and other Psychotic Disorders, are not the only reasons a person may be hearing voices. And as a friendly reminder, having Schizophrenia does not make someone any more dangerous than anyone else.
Hearing voices may be due to having PTSD and experiencing an auditory flashback in which you hear the voice of an abuser say things that you heard your abuser say.
Hearing voices may be due to having dissociated parts of self that are attempting to communicate with you.
Hearing voices or having vivid dreamlike experiences can occur as you fall asleep or wake up and are referred to as hypnopompic and hypnagogic hallucinations.
Hearing voices may be a reaction to medications or substances. I myself have had visual hallucinations due to a medication interaction.
Having these types of experiences does not make you sick, broken or disturbed. What matters more is how having these types of experiences affects you and how you make sense of what is happening.