Some songs can't be played using Music app on iOS When I open the music app, some songs have stop signs next to them, and whenever I want to pick a song it goes past it and then past a few more and then stops at a different song.

Also I can't hit the back arrow to go backwards through songs — the screen will go back temporarily and then remain on the song it was originally on.

How do I fix this? I can't listen to songs I want, and I can't move around with ease, it does it all for me.
The stop sign shows that the file can't be played. This is usually due to a corrupt song. When the music app attempts to play one of these corrupt songs, it fails and skips to the next song. This is why you can't go back a song, since when you go back it attempts to play the song, fails, and goes forward (back to the song you started at).

Make sure that the songs play in iTunes, then delete the songs from your device and re-sync them from your iTunes library, making sure that the sync is complete before disconnecting the device.