IPhone charges but won't sync to iTunes?

Using the same computer (MacBook pro) same chord. Same phone. I've tried both my iPhones and they won't sync, only charge. I really want to add more music. It stopped working recently.

Try rebooting the phone back to it's factory settings. I have had this problem also. I rebooted the phone (Under settings app) and it synced right back up to my computer!