I have a problem with iTunes (latest version) freezing when connected to my iPhone 5 (iOs 7.1.2) via USB. It connects with my elder MacBookPro, with that iTunes, but not on my iMac. There doesn't seem to be anything wrong with the cable since it connects very well with iPhoto so I guess something has been messed up in iTunes itself. What can I do to fix this, reinstall ITunes or is there any more easier fixes? I have reset the SyncServices but that didn't help and I have tried different cables too but the beach ball keeps coming back after each tryout (and freezes, not continues to work).
I would suggest you download and install a fresh copy of iTunes and report back.
Before doing that, though, I suggest you create new user account on the iMac and see if iTunes hangs up when you plug in the phone. If there is no problem, then perhaps something is wrong with the iTunes preference files for your account.
Lastly, you might want to sign out of the iTunes Store (if you are currently logged in) and sign in again.