I've been experimenting with my voice especially at the higher notes to achieve that "grit/raspy" sound which what lots of rock singers always did. Sometimes I manage to get that "grit" sound but it feels uncomfortable to the point I keep coughing. This is my cover of she's goneas you can hear there are lots of strain I did to get that "grit" sound but it did not comes out. Haha. Any tricks or tips on how to achieve the grit?
Simple: you have two choices. I recommend the first.
First: get a voice teacher. Learn basic singing and breath control, then learn screech & fry techniques.
Second: do it on your own and damage your vocal cords beyond repair in short order.
Don't mess with your voice. You can't go to Guitar Center and buy another one.