I used to have pretty bad sinus. I used to take antibiotics for 10 days a month and would be good for 20 days and this goes on each month. After 6 months, my immunity has gone to shit. The doctor recommended clearing out my sinus by a surgery but apparently that doesn't solve the root cause. It can happen again and again.

I tried multiple doctors, treatments, tips etc and etc nothing worked. I finally visited a homeo doctor who diagnosed it right. It's deviated septum which is causing sinus infections because of regular coconut water intake. I just stopped drinking coconut water and it's been 10+ years and not another recurrence of sinus so far.

Proper diagnosis is hard and requires skill. The OP figured it by himself and in my case, someone did.