How to stop iPhone 5C screen from going to spotlight search.

I repaired my I Phone 5C screen and everything is working fine, but sometimes, quite often, I will try to slide the screen left to right or click on something, when ever I just try using the screen in general, it will suddenly go to spotlight search, open up random things, etc. It just starts moving, opening and anything on its own as if a ghost is touching my phone. I tried a new screen and unplugging the battery and putting it back in, but I can't get it to stop messing up.