Thanks for your question.
Yes, chronic sinusitis can cause dizziness. Your sinuses are also important to keep your head 'balanced'.
Chronic inflammation may result in mild dizziness.
Hopefully, following surgery your symptoms will improve.
Another possibility is middle ear infection, as sinus infection can affect the ears as well.
This can also cause dizziness.
But, if your ear are ok, then sinusitis is likely the cause.
Good luck with your surgery!