Hi, I suddenly developed tinnitus (ringing in the ears) back in November. It was in one ear, and occasionally it gets louder for a few seconds, also. Sometimes the other one rings, too.
I went to an ENT specialist and also had an MRI after the tinnitus began, and there was nothing wrong with my ears or hearing, and the MRI came back normal. The doctor said sometimes it just happens, and anxiety can exacerbate it.
Sometimes these things occur with no explanation. It could be from listening to your music for days like you mentioned. I should add that before the tinnitus began, I was vacuuming with a loud vacuum for a while that day, but I'm not sure if it's from that since I still have the tinnitus. I have learned to ignore it and don't even notice it anymore unless I look for it.
I hope this helps!