I have this issue as well. I just purchased an album and it shows up in my purchased playlist but not in my music library. I do have Itunes Match turned on and I have verified that the files are in the correct directory. I've tried to import the folder to my library, but still they don't show up.
I am having the same issue. I have recently added music not show up in the music section. I have a smart playlist that I created a while ago call all music and the newly added items show up there.