I don't know if you're familiar with the term for when an overly simplistic melody gets stuck in one's head, which is earworm. (And which is what makes Rickrolling such a dangerous activity. "Never gonna give you up, never gonna say goodbye.." should I have put a trigger warning on this response?)

But it makes sense that there would be a positive version of this; I use music to self-soothe in a similar way, in fact, if I've neglected to treat myself to what I consider to be music therapy, on any given day, I absolutely notice the difference. I think good music provides an abstract landscape, or a prism, in which our brains can do some of their better conceptual work. After all, if one automatically "feels better" as the result of listening to preferred music, it stands to reason that we've been comforted at a subconscious level in a meaningful way.

It could be related to obsessive-compulsive traits. Wikipedia indicated that those with OCD (and, those who are in the music biz) are more prone to earworms, however I wouldn't put too much stock in this since they also indicate that 98% of people get them. Maybe people with OCD (and people who love music) just get them more often? IDK.

(In case you ever need an antidote though, there's actually been research done on how to get rid of an earworm. "Scientists at Western Washington University found that engaging the working memory in moderately difficult tasks (such as anagrams, Sudoku puzzles, or reading a novel) was an effective way of stopping earworms and of reducing their recurrence." Er, so just think about something else then? I wonder how much this research cost..)

But personally I don't often have any problem with earworms, and while they say music lovers are more prone, I think it's why I'm not, because I have a large working library inside my mind, of melodic phrasing that I prefer and can call upon. (Although I confess, at the moment I am noticing that I accidentally Rickrolled myself. "Never gonna give you up..")

(I am sorry. For everything.)