Hello- I had endoscopic sinus surgery, due to chronic sinusitis, in April 2017, but now have severe sinus pressure on a daily basis. I did not have this pressure prior to the surgery. It has started to trigger severe migraines that last for days. Been back to my surgeon and he has no answers. I’ve changed my diet (cut out dairy, gluten) and tried everything else in the book to try and relieve it. Any idea why I’m having this?