Q: Trouble removing songs from Phone

Before I switched to apple music I had about 500 songs stored on my iPhone SE. I upgraded to Apple Music and I love it however, I can't get rid of the original 500 I had stored there. Every time I plug my phone into my computer it syncs and shows me a 'playlist' called music and gives me the option to update the playlist by adding more music. I can't find any way to delete the 'playlist' containing the original 500 songs. It's very frustrating as I would like to only store my Apple music songs on my phone. It also shows the storage space those songs are taking up. Please help me remove this music, preferably without deleting it completely from my computer.