Why won't iTunes let me delete songs from my iPhone 4S?

I have never had any problems with deleting songs, but after installing the newest update, I have been unable to untick things in my iPhone's music or delete anything. I can still delete on the main iTunes library.
Please help

You should do some research on it it see if they have anything that can help You but if you can't you should call customer service and they might can help you hope that was helpful enough