I phone 4 question

[gabagoo]

I have had my phone for over 6 months now but as of late it seems to dial out on it's own from being in my pocket.
I can't find a way to lock the phone....is there a way?

 

[ucmj22]

before you put it in your pocket, hit the button on top of the phone

 

[Signs 365]

Put a passcode on it...that could help too. Mine does that from time to time.