Why can't I sync songs onto my iPhone?

So I recently just got an iPhone 4, and instantly I have tried putting music onto it. But for some reason I try to sync my phone with my iTunes (where every song on there I imported from my legitimately purchased CDs) and it says all of the items (the songs) can't be synched. Does anybody know why?

Does your iphone reset after updating?

So I'm going to update to iOS 7 today. And I don't want to lose anything. I know to back up my phone, but I was wondering if it deletes everything after it updates so I have to put it back on.

APP NOT UPDATING ON IPHONE 4?

I enter in my card details i got money on there it says declined!
updating for apps won't go through unless i get through that part first…

what do i do?