Original post by: EasyIFI ,
Did you recently drop your phone? I had the same thing on my Samsung Galaxy S3, when it was in my pocket, it randomly turned on and unlocked itself (it didn't have a passcode or anything). Is the screen dirty? Try washing and drying your hands to get all the dirt off your hand, and use a screen cleaner to get all the dust and stuff off the phone screen. Sometimes that interferes with the touchscreen.