I sorta have the same 'problem'...but I like it. It doesn't matter where or how I sleep, or for how long....and there is no specific time during the day/night it happens.
I just make a mental note of when I want to wake up, either from sleep or a nap...and I wake up to music. I do not even own an alarm clock.
Years ago when it started, it was incredibly loud, and I had a vision/dream of a radio with no knobs so I couldn't turn it down. When I woke....it was dead silent, and head felt like I just stepped out of a concert. The 'radio' is gone now....the music much quieter....and is rarely anything I like, or listen to during the day.
Another weird thing....if I wake up without it...like having to use the bathroom or something, I cannot wait to fall back asleep...and do not feel totally awake until I wake to the music.
The accuracy is amazing....way better than an alarm clock. I have never been late for work.
I like this tune.
www.youtube.com/watch?v=BVZRFFu7VlQ
Have you heard of the 3 o'clock prayer? This was happening to first my mom and then myself for awhile until someone told her about this 3 o'clock prayer and about the Divine Mercy and so she started reciting this when she would wake at 3 am and it stopped happening. It worked for me too. Now I still pray the 3 o'clock prayer but in the afternoon instead since she sleeps all night!
Here's a link that can explain it better.
http://thedivinemercy.org/message/devotions/hour.php
Hi, welcome to the forum, if one perceives something which is not there it is known as hallucination. You are hearing music which is not actually present and it suggests of auditory hallucination. But the presence of such symptoms in the night time is bit unusual.
This may be psychiatric abnormality. Also another possibility is continuous ringing in your ear known as tinnitus due to ear problems. The possibilities for tinnitus are Vascular disorders including Arterial bruits, Arteriovenous shunts, Paraganglioma, Neurologic disorders, Eustachian tube dysfunction, Otosclerosis and Vestibular schwannoma.
You need to undergo complete ear examination supported by brain MRI to rule out any organic lesions. If ENT evaluation result comes normal then have a psychiatric consultation too. Listen to relaxation music and meditation will help. Take care and regards.