Not when I use them, but when I'm not using them. Sometimes I get a high pitched squeak when driving down the road. If I turn the wheel at all, it goes away. Just happens when I'm going straight.

Any idea how to fix this?

 

Use OEM brake pads. I have had the same problems with every set of aftermarket pads I have ever used on a Volvo.

 

Sometimes the rear pad springs will do that if they aren't seated all the way.