Q: iPhone 5S speaker not working- Barely 1 Year Old

So, earlier today my phone was totally fine. I could play music with no problems, and my ringer was working. Now, all of a sudden, my speaker doesn't work. When I restart my phone it will work for about half the length of a song, and then it seems to mute itself. The song keeps playing, but no sound is coming out. My ringers won't work, and it is NOT stuck on headphone mode. I haven't dropped it or gotten it wet. I have no idea why this is happening and it's extremely frustrating because I feel like I just bought this phone. When I put headphones in, I can hear songs and ringtones through them without any problems, only function that seems to be lost is the actual loud speaker.