Is it normal to hear voices inside the head

It's not a problem until you start replying to yourself. I have only been told this, to me it's normal. The voices in my head and I are great friends; we have long conversations and sometimes they even make me laugh. I promise I'm not insane; as far as I know anyway.

I don't know if it's normal but I often can't fall asleep because of the voices and or music that will relentlessly play for hours in my mind

As long as it's your own thoughts and you aren't hearing other people's voices in your mind. Maybe you are thinking of other people's voices? If you can tell what voices are real and what isn't then you are ok. Also, it's normal to have a song stuck in your head... Is that the music you are hearing?

No it is not normal I am not here to judge you though. You might have an undignosed mental illness. I somewhat experience this but is it was my inner voice speaking in my head. I overcame hearing that noise in my head. Therapy, sleep, proper medications. So you can overcome it too. Stay strong.