Help media sound dont work! help!

[carocarm]

My media sound doesn't work. My mp3 files play but no sound comes out. My Pandora plays but no sound comes out. My phone rings when someone calls, my recieved texts makes a sound. All works fine but not my media. Can watch nor hear n e music. i have my volume way up for everything. I can't figure out what's wrong it worked just fine yesterday help help help! Please! Thank you-caroline-