Why is my iPhone calling random people?

I know a lot of people have asked about this already, but my iPhone 4 keeps calling random people. I'm always getting phone calls back from complaining recipients of my supposed calls, and I'm getting tired or having to repeatedly apologize to people I don't even know. Until now, I've had my iPhone for almost two years, and i never had a problem with it. Then a few months ago, all of this just started and i don't know why. I've looked all over the Internet, but i still can't find a straight answer. The closest to a solution I found was either resetting my iPhone 4, getting a new SIM card, or call Apple (which I of doubt will help solve the problem).Is there a better solution out there that has maybe worked for you personally, or am i better off to just press reset?

Sometimes I butt-dial people LOL. Maybe thats it.

In your i-phone setting problem please right your setting and get exact functionality as you want