I'm missing a couple of playlists from my iPhone, but they are still in iTunes?

Recently I added some new music to itunes. I added these songs to my playlist on itunes, but then the playlists i added them to disappeared from my iphone. I tried syncing my phone with my computer, but that didn't work. The songs are still on both my iphone and itunes. The playlists are still in itunes. But they are not on my iphone. These are playlists I use the most and would appreciate any help in getting them back!

Buy a android.problem solved