I believe your face is just touching the screen and whatever its touching has heptice feed b and soud.
Try this, go into settings > sounds and display> and uncheck the following: audible touch tones,audible selection, and heptice feed back.
Now keep in mind if u do thisit will disable this feature for everything on urr phone, such as vibration when u touch a soft key.
But this way u can see if that is in fact whats happening.