I’m going to weigh in here and start by stating that I think a lot of the posts here are BS speculation. I had the ghost touch issue recently. It was fine until suddenly one day it wasn’t. Most touches would elicit no reaction and suddenly random text would be entered, texts sent and apps opened. Some posts suggested a loose screen connector. This being the easiest problem to diagnose, I opened up my phone, and sure enough, one of the three screen connectors was loose (iPhone 5S). After reassembly, the symptoms were completely remedied. If you have this problem with ghost touches, first check the connection before deleting apps, or suspecting a faulty digitizer. Apparently, sudden disengagement of the connectors is possible. I should add that recently i replaced the battery, so that could have put tension on the connector, causing it to become gradually loose.