iPhone 4s Speaker Not Working

My iPhone 4s is about 5 months old. The speaker started giving me problems the other day out of nowhere. I can still hear phone conversations through the normal ear-speaker and the headphone jack works. I cannot, however, hear anything when my phone is set on Speakerphone and approximately 98% of the time I cannot hear any update tones, music or video sounds. The music, video, phone call, etc..is still working, I just cannot hear it. Sometimes, the music (or ringtone, etc) will start where I can hear it for a split second and then go silence. It's almost like my speaker is blown, but yet it still works for a second or two every now and than.

I made sure to turn my 'Bluetooth' OFF and have tried restarting the phone, etc.. Anyone have any other advice?