IPhone 5 opening apps and typing?

About a week ago, I got a screen replacement for my phone. Everything worked perfectly fine. Maybe 3 days after getting the new screen, I updated to iOS 7. 2 days ago, on Instagram, I was trying to type a comment, and my phone started typing on its own; ntjzkksllsbbauwkxnnzzzzndnnssowl
As soon as I locked my phone and unlocked it, I had no problems.
Today, I pressed the home key, and it opened kik. So I closed kik. It reopened. This happened maybe 5 time. So I locked my phone, unlocked it, and everything was fine.
Can't quite figure out if this would be because of the screen change, or the software?
Again I had no problems with the screen until I updated my phone to iOS 7, 3 days later.

You can try turning off the phone completely to see if that helps. A complete reset could also help. This could be from both the update and the new screen, though it is more likely the screen. See if you can get an answer from whoever fixed the screen in the first place, they might have another solution.