Why won't music download to my Iphone?

So I synced my Iphone to itunes to add a few songs and when it finishing syncing, I tried to play it on my Iphone and it wouldn't. Like they appear on the phone but it won't let me click on them and instead of being written in black they're in grey. How can I fix this?

If you need to download Iphone music then see the source link
and remove the (bracket)then copy and past in a new tab and complete the task you get lot of music for download…