LSS

I had the most severe bout of last song syndrome or LSS. After seeing Howie Dorough perform with Sarah on ASAP last Sunday, their song has stayed with me for the last two days. It's kind of weird because I think I can still hear their duet even when I'm asleep. Because the song is so catchy, it has been ingrained deeply in my brain. This made me wonder why people experience LSS at certain points in their lives. Is there a scientific explanation to it?

Meanwhile, I'm posting Sarah's and Howie's duet here.