Car is making a high pitched squeel noise when turning sometimes. Any ideas on what it is?

Seals in your steering rack.
 

I have the same problem on my partners Passat-B5.

Its can be expensive, as the rack is a PITA to get out and recondition the seals.

Change the Power Steering fluid, bleed, and cross your fingers. PS, Make sure you have the correct Fluid. Our car developed the swollen seals from the previous owner using incorrect hydralic fluid.

Does it become unbear able?

I know it's not low on P/S fluid because I'm sure as soon as you heard the noise you checked the
 

fluid level ASAP,right?

Happened to me...was the steering rack.
 

very expensive!

Ours is stable...
 

It hasnt got any worse. We did change the fluid though. I suggest you do this ASAP.