Adobe Audition Sounds Different Then Anything Else

I am new to the Audition and do some basic sound correction. My problem is when I am editing an audio, the sound output of my PC changes completely. For example, I am editing a project on Audition, and watching a Youtube tutorial. When Audition window is active even the sound of youtube video changes and kind a have little noise and bad quality. When I deactivate Audition window youtube video sounds at it should. Also my exported audio sounds different then it is in Audition. Do you know what is wrong with my setup?