My Iphone 5c won't sync the music?

My iphone 5C won't sync music back. It only has music that i purchased but music that i previously had burned off of CD's are no longer on my iphone but are still on my Itunes. Anyone have an answer for this?

I don't understand why so many people use sync to put music on their phones. It's not like it's the only way to put music on an Apple device,

I never sync any of my Apple devices to put music on it. Instead my iTunes is set for manual management of music and video. I almost never have problems putting music on my iPod and obviously much fewer than those complained of in questions like yours which are posted here in the thousands - including loss of music to put songs on my iPod.

Manual management is just clearly superior in every way and it works on iPods, iPhones and iPads both new and old. I've tried it on first generation nanos, iPod 4, iPad 3 and iPhone 5

You enable manual management by bringing up sidebar in iTunes (ctrl S if you don't have it up already) and clicking on the iPod tab. The main window should show you the main summary for your iPod. The box for the manual management option is at the bottom of the page (it's probably already checked).

That's basically it. Now you can just drag the songs from whatever folder they're in in Windows and drop onto the iPod tab on iTunes sidebar.

Every time you update iTunes, you need to reboot your computer.