Why is my phone has black screen but still can be touched?

When i turn on the phone it blinks white light that disappear instantly ... then its just a black screen ... as in no light at all ... it looks like its dead ... but i know it open cause when i randomly click on the screen i can open an app ...

But rarely sometimes, it open normally, like theres nothing wrong at all times ... i can use it like a normal phone ... but again after sometime it goes back to being dead screen ... happens rarely ... most of the time its just black screen

Also on rare occasions when you turn it on, it the screen lights up a plain white/pink screen

It start when i put my phone in my pocket with a pen ... but the screen is not cracked ... no black patches when it opens normally

I already done factory resetting it when it opens normally ... didn't help at all

Sooooo ... what happened to my phone hahahahaha .. is it an easy fix? Like a disconnected something inside the phone?