My phone enters the certain app without my command why?

@deogratiusjacob you could be dealing with some malware, if it is alway the same apps. Try uninstalling those apps. It is also possible that you are experiencing ghost touch, which is what happens when there is an issue with the display assembly.

Try to place your phone in safe mode and see if that still happens. If it does consider replacing the display assembly. To place your phone in safe mode you power off the phone, then press and hold the power button and volume down button simultaneously until the phone boots up, then release the power button while holding the volume down button.

Since iFixit doesn't yet have a specific guide for replacing the display, use something like this video Replacement screens are readily available at many online sites.

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!