hi, its a hardware fault and most likely, you will need to replace your touch screen (it is safer to replace both your touch screen and LCD).
It is caused by microUSB charging port (at least in my case).
Go to developer settings (if you dont have a developer options in your settings menu, activate it by tapping "Kernel version" line in your "about phone" settings. Google for some guides to activate developer mode if you still dont activated it) and in the developer options, thick the "Show touches" option, so you can see when and where is your phone doing these weird touches.
You can bypass these weird touches by moving around and pushing the microUSB conector .. applying different pressures and angles with your finger on it would most likely find you a sweet spot, where these touches dont occur.