Why the touch is not smooth

@jensenm all of this "stuck and not smooth while scrolling and sometimes ghost touches" sounds like you are having a failed display assembly (touchscreen). Replacing the assembly should fix these issues.

Since iFixit does not yet have a guide for this, Use something like this video or use the instructions from here to get this accomplished. Replacement screen are widely available at many online stores.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!