When I try to play a song with the music app on my iPod Touch, some songs freeze at the beginning and my iPod touch becomes unresponsive to anything for up to twenty seconds. Help?

Hi all I'm new here.

My issue goes something like this. When I use the standard music app to play some of my music (MOST from Beatport) on about half of the songs, my iPod will freeze and become unresponsive for up to a half minute. After that, it normally brings me back to the playlist song selection that I was looking at previously. I have an iPod Touch 5th Generation that is running iOS 6.1.2. I have only three playlists, but all of the three have over 500+ unique songs on them. (I normally don't keep duplicates of songs on my iPod) I started to have this problem when I upated my old iPod Touch 4th Generation to iOS 6.0.0. Ever since I got that update, half of my songs have not and will not play.

I have tried numerous times to reset my iPod (4th and 5th) and I even re-installed everything without using a backup.

Any help as to what will fix my problem?