Hi I Have Been Suffering From Swooshing Noise In Both

Hi I have been suffering from swooshing noise in both ears wich comes on usually depending on my posture, if I lay in bed the wrong way or sit the wrong way it comes on and then lasts around 20 seconds settles then I get light headed for a short time, I also have a type one Chiari and have recently had a pressure monitor in the head which indicated high intercranial pressure and would benifit from decompression surgery, im worried about the swooshing noise , ive had it since early 20s im 51 now.