black bar on 2009 macbook?

so i have a late 2009 macbook and i noticed today that i have a black bar on the right side of the screen.

it's much thicker than de rest.( the display has thin black lines all around wich is normal but this one isn't i think )

i have no idea if it was there all the time or if it appeared today. ( i only noticed it today 😟 )