I am always queued with the best players that know what to do in any situation , will always know what position you take and will totally headshot you if one pixel of your hitbox shows up on their screen. Why??? Can somebody explain?

I'm trying to learn the game and can't figure out specifically what these 2 things do. The white one seems to fade and the red may be yellow/orange at times. They seem to indicate some sort of enemy activity but I don't know what they are c...