Can't sync/unsync music to iphone6

When I connect my iphone 6 to my pc, itunes recognizes it.I click on my phone. But when I click on music on the left, nothing shows up now. There used to be options where you could put music on the phone by album, artist, etc. Now it's just gone. I tried dragging and dropping single songs to the phone and now that won't work either. Both my iphone and itunes have the latest versions. I've had my phone since November and have synced music many times with no problem. I've inserted a screen shot to show what I'm talking about. Any help would be greatly appreciated. It's very frustrating.