Music won't play from download app?

Okay so i'm freaking out. I had a music download app on my iphone and i had a ton of songs on it but i wanted them in my actual phone so i didn't have to listen to them "in app only".so i put them in folders on my computer and put the files fron the app in my itunes. They play absolutely fine on itunes. So i synced my phone with my computer and i synced all the music from the app on my actual phone and the songs show up on my phone but when i click to listen to one it plays nothing. No sound, it just skips that song. I don't know why it won't play but i'm freaking out! Sorry this is long but ill give 10 points

Try this link to Apple - iTunes support:
http://www.apple.com/...rt/itunes/
and you can contact Apple support here:
http://www.apple.com/...es/contact