How to change the lobby resolution so it'll fit my computer.

Alright well I just recently started playing CA again and for some odd reason, the lobby and after match screen resolutions is nothing to do the in game resolution. I tried changing it via settings but it only changes the in game resolution. Is there a way to make it work for my computer screen so this way I won't lag as much? If there is a way please let me know, I feel foolish for even asking.

No, I meant the lobby game, not my computer. My computer resolution is perfectly fine, it's at its max. I'm talking about, when I'm in the lobby, the screen is stretched out to the right so I'm unable to go straight back into the lobby after a match.