1999 Buick Regal gs supercharged. Y is it whining when I turn my wheels

It is probably the power steering pump. When you go straight, there is no demand on the pump so no noise. When you turn the pump is working....the more you turn the more it needs to work, also the slower you are going when turning you are probably noticing more noise. With a few tools you can replace the pump with a rebuilt unit. You may need to watch a few videos to help....when you get it installed, there is usually a process to go thru to get all the air out of the lines.