How to get rid of a song on my iPhone that's synced by iCloud?

I have no problem putting songs on my iPhone and deleting them normally, but I have this one song which has synced from my iPod which I don't want anymore. I can't find a way to delete it, it's really frustrating me. I've tried swiping to the left and right but no delete button comes up. I've also tried signing out of iCloud and switching all the settings off but that didn't work. I have been thinking on what to do, and I thought, what would happen if I was to Restore it to factory settings? I know it would take everything off it. I've thought about that, I've wrote down my apps so I can re-download them but would it permanently delete this song I don't want? I know I'm making a deal over it because it's one song, but I really don't want it anymore. Any ideas? :/

Deletetinoz

Log into Itunes plug in the iphone and under sync settings deselect the song you don't want to sync

It should stay on the iPod and be deleted from the iPhone.
HTH
David