Possible Clues:

• Far-too-memorable song
• Song that's stuck in your head
• Overly catchy song
• Annoying tune — more war (anag)
• Tune that stays in your head too long
• Song that you hear all the time
• Irritatingly catchy tune
• Song that's hard to get out of your head
• The 1975 hit 'Can't Get It Out of My Head' would be an appropriate one
• Tune you just can't get out of your head