What they said plus Mucinex (or the generic) makes the goo more fluid so it can drain out faster/better. Irrigation with a neti pot or sinus rinse bottle can be a huge help too. Use 2 packets of the salt that comes with the bottle; the extra salt helps draw water out of the tissue to reduce swelling. Try to snarf the water down the back of your nose and spit it out of your mouth.
Good luck. PND is annoying AF
Damn. I didn’t realize. I have had it recommended by a doctor for mild sinus infections along with an anti inflammatory and it seemed to help, but I must admit I didn’t check any studies. I will say that the few I did find were about coughs, which could be different