There seems to be confusion here about appropriate diagnosis & treatment. For example, it is not clear whether your condition is external or middle ear related.
The history of onset, complaints & treatment for sinus infection you have reported are suggestive of a middle ear problem, yet treatments such as various drops in the external auditory canal are only useful in protecting the canal. If you have middle ear congestion or infection, they are of no benefit whatsoever. They also are not useful in protecting or treating sinus conditions.
As such, BigJet's recommendation that you see a dive medicine savvy ENT is a good one.
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.
Best regards.
DocVikingo