sensitive keypad iPhone

Sound like it may be your proximity sensor, which should turn your display off when you raise the phone to your face, preventing you from accidentally touching the controls (mute, dialing, etc.) when you're on a call.  Try raising the phone to your face as if you are making a call and see if the display turns off (look in a mirror if you can't see it).  If it doesn't, try cleaning the screen, expecially near where the receiver is located at the top (this is where the sensor is located).  You might also try removing your screen protector.

Do you have a white iPhone? If so, do you have a case or screen protector? Take them off and then try making a call and then covering the little black oval above the speaker, if the screen goes black it's working. S,eti,Ed the covers and cases on the white phones can refract light strangely and make it so the sensor constantly receives light.

If so, try removing* iPad typing is hard... Waiting for my retina MacBook pro, 1st world problems.