iOS 7.1, iTunes 11.1 Syncing Issues (iPhone 4S, Macbook 2009)

Hi,

Ever since I updated my iPhone to iOS 7, I have not been able to sync it with my Macbook. It never appears under the "Devices" tab in iTunes. My dad synced his iPhone 3GS to my computer for as long as he had that phone, without a hitch, but when he upgraded to an iPhone 5S, it would not sync properly either. This leads me to believe it is a bug within iTunes on the computer. Also, when I connect my iPhone, it incessantly pops up the message, "Do you trust this computer?", to which I always choose "Trust". I have used my iPhone as a personal hotspot via USB cable before, but it never had any issues with syncing until updating to iOS 7 and iTunes 11.1.

Any thoughts on possible solutions? Let me know if you need any more information.