iTunes won't read my iPhone 5!!

I just bought my iPhone a month ago and it had been working fine until I got a problem with iTunes sync. So, just now I got this message from iTunes

"iTunes cannot read the contents of the iPhone “Shendy’s iPhone  ”. Go to the Summary tab in iPhone preferences and click Restore to restore this iPhone to factory settings."

Before the message appeared, I could easily sync and everything worked fine. Can anyone help me ? It is really annoying if I gotta restore and re-sync. Wasting much time! Thank you 🙂