After lots of in-depth independent research, I am 99% certain I can give you a good solid explanation of why the heck I see music.
Basically, they call it “synthesia” (spellings vary) and it’s this neuroligcal thingy where the senses are crossed. Some people have it where they can smell colors, taste sounds, basically any combination of senses that are all jumbled up. Some people are “projective” which means they physically see/smell/hear/taste something from the other sense tells it to. The most common one I looked at was audio/visual and the sound-created picture basically covers up what they actually see. Or they really taste the texture. Very overwhelming.
Or, there are people like me who have it very mildly and either just see it in their minds eye or head voice or whatever and some have to really focus to single it out and undersand it.
The reason I am so sure I have this and am not just nuts (of course, I could very well be wrong I’m no doctor) is because of the other issues people with synthesia routinely have that I have, in fact, been officially confimed to have or family has. Not to mention well, how else do I explain that when I focus on music I can see the corresponding colors, line direction, width, transition etc.
So yeah. That’s basically it. I have yet another neuological disorder to add to my list that is a frequently undiagnosed diorder of the sensory nerves.