Hearing a song repeatedly may make this more likely. But repetition is not the whole story. In experiments with unfamiliar songs, some melodies returned more often than others; researchers also look at rhythm, melodic features, and chance reminders in the surrounding environment. There is no single formula for a “catchy song.”
The tune does not have to be one you like. Sometimes an advertising jingle stays with you longer than a piece of music you chose yourself. It may have played while your attention was elsewhere, and later a similar sound or word may have set off a short chain of memory. We cannot always identify the exact trigger.
Usually, this kind of inner replay is a feature of musical memory, not a secret message. You can let it be and get on with what you are doing; for many people, the tune gradually loses its grip. If you are curious, ask yourself: “Where might I have heard this tune recently?” Sometimes it is enough to remember the last time it was playing in the background.
The stars speak. The choice is yours.