I was using postman fro a long time IDK why i am getting this issue now
When I set any params in Headers it append it to the URL and actually nothing passed in the header and its not working
Welcome to the Postman Community! 
I’m not sure I follow you here, in the image, you’re added the store key and ar value to the Query Parameter which appends this to the URL ?store=ar.
This is not the Headers sections, that would be under the section that currently have 25, according to the image. The inputs look similar but these are separate functions.