Trouble adding more music to player on phone

[jazzyjohn]

In the last few days, after having no trouble at all, I'm suddenly having problems adding more songs. When I look at the song list, I see that the songs I've just added are listed, but when I try to play a song I've recently added, there's no time length on the side like the songs I've added before, and the player skips to the next song that does work. I've still got quite a bit of microSD space so I don't think space should be a problem. Any ideas?