Hello @gtl, I think the answer is yes according to this information I found. The article also has some home remedy suggestions you might find helpful.

"Sinus drainage is a natural process, so a person cannot prevent it. The sinuses drain down the back of the throat and into the stomach. Each time a person swallows, they are swallowing some mucus. Symptoms occur when there is an excessive amount of mucus, and the mucus is unusually thick."
-- Sinus drainage: Natural home remedies - Medical News Today: https://www.medicalnewstoday.com/articles/323569

Have you discussed the symptoms with your doctor or ENT or tried any over the counter product to see if they might help?