I'm sure this one is just a PEBKAC error, so please bear with me since I am new to Android.
I've uploaded all of my music to Google Play Music and I can see all of my songs via their web interface. However, on my Moto X, there's at least one song missing. I have tried refreshing the Google Play app on the phone to no avail. I haven't had time yet to go through all of my hundreds of albums to see if any others are missing songs, as well. Any thoughts?