Sinus problems are often caused by infections and antibiotics are sometimes prescribed, along with decongestents, topical
nasal sprays, etc.
You can help symptoms by usin a saline solution, like Ocean, or getting a neti pot and doing irrigation several times per day.
You can also get OTC nasal sprays like Flonase, I believe, which are steroidal topical meds that don't enter the blood stream.
DON'T use AFRIN. It's addictive and causes rebound congestion.