Try resetting the phone
"Begin by holding the sleep/wake button at the top right of the device and the Home button at the bottom center of the face at the same time.
Hold them both until you see the screen go black. In some cases, you may need to keep holding them even after the red power-off slider appears. If it appears, just keep holding it.
Wait until the silver Apple logo appears.
When this happens, you can let go - the iPhone is rebooting."
Hope this works for you. If not you may have to reset to factory settings (make sure you iCloud everything first though) as I can't find anything on google about iTunes problems with ios7.
Good luck