Screen "Too Sensitive?"

My Samsung S3 will not stay still. I do not use a holster, preferring to slip it into my shirt or jacket pocket. That was OK for a few months, but now the screen "wakes up" at the slightest touch. It will even turn on if I simply wave my finger at it! When it wakes, the voice command app starts listening and chirping for attention. I have even had the phone respong with "calling headline news" when it overheard the TV.
It has become such a problem I have to shut the phone off completely to get through business meetings without interruption.
It there a custom setting or other solution to get the phone to stay on, giving silent vibrate notification of messages, and as I never use it, disable the voice command feature?

Ideally, also, would be a way to "safe" the screen, so that it took both a push of the button on the right side of the phone and another action such as pressing the bottom center button or one or both of the volume buttons to cause the phone to "wake up".