My iPhone 4S volume stops working?

The volume on my iPhone will work for a few seconds then it will stop. Then it will start working again. I turned my phone off and turned it back on and it only worked for a few seconds. If I put headphones in very thing is fine. But I can't walk around with headphones in all day. What can I do to fix this?

Do you drop it? If so, that's why.

Retunr it and get new one