Whooshing sound is really common and it can happen due to many causes
Most of the time it is a minor issue like local infection or even wax in the ear
Since it comes when you change your position it may also be related to blood pressure either high or low
Next Steps
Get an ENT specialist consultation and proper otoscope examination of the canal and drum
Then get an AUDIOMETRY test done along with Impedance
depending on the findings of the two above we can proceed further
Health Tips
Do not put ear drops or buds
Do not listen to loud noise or music for long time
Do not try to meddle or clean your ears by yourself