Only one side of t=headphones work.

I thought I broke my headphones. But I didn't. One day I decided to play music and sound only came out of the left side. I though I broke my headphones, but I plugged in another set of stock headphones and the same thing happened. Then I tried those stock headphones on an old iPod,and both sides worked fine. So Im wondering what happened to my phone, and how can I fix it, do they replace it, and how much. The issue I have it is that, when I plug it into my dock, they music comes out on both sides. Meaning the headphone jack is messed up. I see a white circle in there(probably for water damage). My second is, is there a product(other than nano lanyard headphones[which I would use but but my phone is too heavy]) that plugs into the dock connector and I can listen to music.

Thank you.