music missing after hard reset

Good morning,

I had to do a hard reset of my iPhone 6plus with ios 12. I backed it up to my computer using iTunes. my phone shows music in grey with dotted circles in the music folder on my phone after re installing backup. it will download the songs I purchased with iTunes but not the music from cd's I downloaded in the past.is there an easy fix without having to delete music and reinstalling all discs? all my music shows up in iTunes library and plays just will not go back to phone.

Thanks you for any help