I hear music in my head?

Ok about three weeks ago, i was getting ready for bed when i heard clearly defined rock music out of nowhere. I checked everything that could be the source in my room only to discover that the music was coming from my head. I have an anxiety disorder so you can only imagine how i reacted to this (it was not pretty). Now as i'm writing this question its back (it has been on and off for like 45 minutes) and it has come back since then in isolated moments. I don't remember for the other times but for right now I can only hear it in my left ear and sounds of more just like a drum break with various percussion more than anything else whereas the first time i remember it sounding like a more full band but without vocals. Also, the first time i heard some weird techno music stuff which bothered me cuz i hate techno. If this is something serious please don't get mad at me for sounding like cheery and almost happy about it, I just feel like i have to right now so i can get stuff done ( i have my final exams this week). Yea, I guess I'm just curious if this is like a thing? If it's a problem? If you know anything about this and would like to tell me that would be awesome. ALSO: I'm 15 year old male with no hearing problems. Never never never have i heard voices ( i know that that's bad). Plus, this is more that like hearing your favorite song in your head, to me this stuff sounds real. Ok thanks!