Recently replaced battery, top right of phone is getting warm

Hi, I recently replaced the battery in my iPhone 6s Plus. The battery works fine so far after a little testing, but the top right of the phone (what I presume is around the area where the screen cables connect) is getting pretty warm after about 5 seconds of use. I'm just wondering what it could be and if I need to replace the logic board. The home button, digitizer, and camera all work fine.