Complex sentence: Mellencamp wrote the about his experiences growing up in a small town in Indiana, having been born in Seymour, Indiana, and living in Bloomington, Indiana, which, at the time of the release of the song, was much smaller.
Split into simpler sentences: Mellencamp wrote the about his experiences growing up in a small town in Indiana. Mellencamp was born in Seymour, Indiana, and lives in Bloomington, Indiana, which, at the time of the release of the song, was much smaller.