cant pan left/right with scarlett 2i2 , sm58 and reaper

[dileshlamsal]

Hi,
I am using sm58 mic and scarlett 2i2 to record vocal , in reaper. It seems like , i cant pan them either left or right (Unlike i did with the usb mics ) for back vocals ....might be a noob question as i am still new to this
but i was under the assumption, we could flexibly change it how much we want to pan on a audio....I am just using standard sterio headphone for this.

I have checked the following
1) master fader set as sterio
2) output 1 and 2 , selected respectively at preference

Thanks,