If i shut my screen while music is playing the next time I open it music will not play on built in speakers or through the audio port

Title explains most of it. I i am listening to itunes or any other music program and I shut my screen without first pausing the music, then the next time I open my laptop and try to play music no sound comes out. I've tried messing with the speaker configurations with no prevail. If I restart my laptop everything will work fine again, but this can get annoyying if I forget to pause my music. Also if it's a bigger issue I want to get it fixed while it's on warrenty.