Last night I had the same issue - my iphone 5 with latest ios7 (7.0.2) would not sync all of my music from my computer to iphone.
This worked for me:
1. connected iphone to computer
2. clicked on iphone (tab/button top button right next to "itunes store")
3. clicked on music tab
4. deselected sync music checkbox and selected apply (bottom right)
- all the music selections on the itunes screen on your computer should go grey (not selectable)
- This should remove all music from iphone with exception of purchased music list on phone
- I watched the sync icon on my iphone while this was happening
- Since i had the music app open on my phone i was able to watch the previously sync'd lists go away
5. At this point sync was complete and the only list i had on my iphone was the purched music list
6. Re-selected the sync music checkbox and reselected the playlists that i wanted on my iphone
7. Clicked apply (bottom right)
- at this point i saw the music syncing and all was well
I hope this works for someone else as well....
very frustrating workout night yesterday without some of my favorite beast mode songs....
Cheers and good luck