Music isn't among the items backed up from a phone to iCloud unless it is something you have purchased from Apple or use iTunes Match (in both cases even then it isn't backed up from the phone to those places).
My wife uses her iPhone 4s with a new iTunes on a computer with Mavericks so more detail will be required to figure out why you don't see you phone working. Here's all I know:
iPhone, iPad, iPod touch: Device not recognized in iTunes for Mac OS X - http://support.apple.com/kb/TS1591
Device not listed immediately after upgrade - https://discussions.apple.com/thread/6573744 - try restarting
LincDavis July 2014 post on resetting sync services when iTunes not responding - https://discussions.apple.com/thread/6452007?answerId=26308435022#26308435022
New phone not recognized when given exactly the same name as old phone. - https://discussions.apple.com/thread/6577994?answerId=26760759022#26760759022 - delete all backups from old phone.