Hi.. Thanks for the query. Yes, it is true that long standing infected teeth in upper jaw can at times cause sinus infection due to close proximity of the sinus floor to the roots of upper teeth.. Although tooth infection does not have a direct effect of causing fluid retention but can be secondary to sinus infection.. Your symptoms are clearly indicating towards sinus infection but it is due to your teeth or not, that can be confirmed only with sinus x ray and CBCT. So my advise is to consult an ENT Physician and get evaluated and get thoroughly examined.. If the problem is due to teeth then your teeth will either be root canal treated or extracted followed by a long course of antibiotics, anti inflammatory painkillers and decongestants to clear off infection from sinuses and fluid from ear.. As of now you can do steam inhalation, take pain relievers like Ibuprofen and use nasal decongestant sprays like Otrivin. Hope this helps.. Regards.