How to fix problems with iPhone Music app

[RW4]

For quite some time I've been having problems with the Music app on my iPhone 4S. At first, it was just a bit annoying that while playing an album, the app would display the artwork/cover for another album. But a much bigger problem has arisen: I can't play some selected artists/albums. When I tap on a selected song to begin, nothing happens--but others work fine. Also, very recently, a song will stop part-way through and the app will begin to play another song in the same album. I imagine the best solution would be to discard the app and reinstall. But the Music app, as with a number of built-in apps, can't be deleted; or can it? Maybe there's a way? I hope someone can help. Thanks.