iPhone plays music that was not added to the phone.

I am using a 4s and it seems that ever since the release of iOS 7 my phone plays music that I have not selected to add through iTunes. For example, while syncing on iTunes, I click on the "On This Phone" feature and search the music for say Enya, and get no results. When I'm playing my music on shuffle, sure enough Enya comes up. I have deleted all my playlist that would sync to my iPhone, and have been left to manually add each individual Artist/Album through the iPhone sync page, but still the unwanted music comes up. I feel I should mention that I recently did a restore on my phone and it got rid of a large number of the songs - I had less than 1GB left in my storage, and after the restore it brought it up to about 4GB free. Any help or advice in this matter would be greatly appreciated, thanks!