Re: iphone sync wont stop
Hi and welcome to iMore.
Firstly, make sure you have the latest iTunes installed on your computer.
Which part of the syncing steps does it hang on?
Try disabling auto sync and trying to sync manually. If you can, try a different computer too as when I had the issue, it was missing drivers on my main computer.
Have you checked to make sure you have storage space left on your phone? Sometimes when the phone is completely full, mine wouldn't stop syncing either. Once I freed up some space, it would be fine.
Conversely, make sure that when you sync you aren't asking to upload more to the phone than it has storage space for. Although you probably know this, remember that a 16Gb phone won't actually have 16Gb available for use due to the OS taking up space.