Can’t add songs to playlist

When I try to add songs to a. Playlist it suddenly won’t let me. I have tried turning off and on synch library, restarted my phone, closed out the music app. Made sure I am logged in. It is a family shared music plan and it is active. Phone is up to date.

it also will not allow me to send songs via text message to other iPhones. Instead of sending the song it will say “I am listening to….” And add the song name.

help!