ITunes won't allow me to add music to my Iphone 5c?

I click on a song and drag it to the iPhone icon but it does not work. I can't click manually manage because then all the content on my iPhone would be deleted. How can I continue to adddm music to my IPhone?

Itunes won't allow you, cause iphone sucks

Have you recently updated your iTunes? If so, you need to reboot your computer. I've had 2 computers (and an additional HD, and on top of that an additional format) in the time I've owned my current iPod. I've never had to erase anything to put new music on.

Why do you have music on your iPod but not on your computer? If it was on your computer you could have saved to CD or flash or anything and it would not have mattered what happened to the iPod.