It probably has nothing to do with the USB port...
Plug your phone into your computer, and then scroll the status bar down. You should see a notification "Connected as xx" Select that, then make sure connect as MTP is checked, if it's connected via ptp (camera) it won't allow you to sync files, for what reason so ever...

If that doesn't help, then reflash stock ROM, that usually helps.. With most problems anyway...

If both of these don't work, then I'm sorry, but I can't help you. I'd then call Samsung, and send it in...

LG Simon