I used to have chronic sinus infections years ago. I used to ride them out, or just let them linger. I would blow orange boogers and my head would throb. I had no health insurance to speak of back in them days, so times was rough...LOL. Lately, I got 99 other problems, but my sinuses ain't one. The infections just went away, and I still surf in any kinda conditions (after rains, etc, etc). They can be tough to kick. The blood supply to the sinus cavities is limited, therefore delivering the dose of antibiotics to the site of infection can be challenging. I heard neti pots work well, but I would only do this if you carefully paid attention to the instructions.
My record was 14 sinus infections in 1 year. Then the vertigo started. After 5 bouts of that I had to get the surgery or embarrass myself barfing on others. Got the sinus surgery, fixed a deviated septum while at it. Neti pot 2x a day since and it's been 5 years now and I've only had 2 sinus infections. Everything gets trapped in the upper sinus cavities, hence the pressure. This will act up and then corrupt the whole system. You need a CAT scan to see if this is your case.
I'm having my surgery in March. If you have a deviated septum and/or turbinate issues, its really the only option.