UILocalNotification custom sound is not playing in iOS7
Did you try to turn off "Do not disturb" mode off?I have the same problem, then I found out "Do not Disturb" is on.After turn off that, it all works the right way.
try using .caf file instead of .mp3
afconvert -f caff -d LEI16@44100 -c 1 wolf.wav wolf_out.caf
My guess is your sound isn't formatted appropriately to play by the OS. Make sure your sound is formatted in IMA4 format. Also, make sure your file is in your application bundle, and you should be good to go.
For more reference and similar question, see this SO question.
Choose custom sound for Local Notifications
Here is a link for Apple's Local and Push Notification Guide. It explains the sounds in detail and the default sounds that can be used.