Events happen a lot in Pokémon Go, and it's hard to keep track beyond small changes in the background. For example, music will play in Pokémon Go for a short time during gameplay, namely Ed Sheeran's Overpass Graffiti. Why is music playing and what can you do about it?
The Overpass Graffiti song is playing because there is a celebratory event from November 22nd to November 30th. During the entire event, you will have the chance to capture Totodile, Mudkip, Piplup, Oshawott and Froakie in the wild. Sunglassed Squirtle will also appear as a guest during this event, and if you catch him, you will be able to evolve him into a sunglassed Blastoise.
The celebratory event centers on Ed Sheeran as he hosts a special performance on November 22 at 11am, singing many of his new songs for his latest album. After the event, Overpass Graffiti will continue to play in the background. The only thing you can do is turn off the game music and continue playing. You can also choose to position with the audio settings set to zero on your smartphone. The music won't stay forever, and it will all stop on November 00 at 30pm PT.