IPhone 4 home button not working?

I have had my iphone 4 about a month. Suddenly this afternoon the home button stopped working. It clicks but there is no response, only occasionally after about 30 repeated clicks. I read that I may have too many opened apps, so I deleted all of the opened apps. It worked... but 10 minutes later, I picked the phone up and the button wasn't working. It has been in my lap, on a table, or in my pocket all day. No dropped, no water. Any ideas on how to fix this!?!?!