Bright on right and dark on the left?

[HeroYTM]

I have a blue line going down my monitor and the left side is darker than the right how can I remove it?

 

[Cycloid Torus]

First reaction to your post: turn off the monitor then on (power cycle it)
Then: turn system and monitor off...remove and reinsert cables...restart (confirm firm connection)
Else: https://www.techspot.com/community/topics/guide-to-making-a-good-post-thread.33297/ with particular attention to when problem appeared?, what happened just before that?, age of components?, warranty coverage? and does anything appear as an error in Reliability History?