I dunno about this ear-popper device, but you can possibly fix the pain by holding your nose, closing your mouth, and trying to breathe in or out. With mouth and nose blocked off, the pressure thus exerted can only effect the fluid in your sinuses, either sucking it out or pushing it back towards the ears, as required (if you're going downhill, you want to breathe out, if going uphill you want to breathe in).
I've suggested this method to a few people with varying degrees of success... one of them claimed it caused agonising pain, another couldn't get it to work at all, but it works for me 
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Diagnosed but unconvinced... I reckon I'm just a rude and arrogant wierdo
