I Have A Hard Lump Behind My Uvula At The

I have a hard lump behind my uvula at the back of my throat. It feels like I have something stuck in my throat, but I don't have trouble swallowing. I saw my primary physician, who said I may have some post nasal drip. He has put me on a nasal steroid spray and antibiotic. I'm on day 3. It's very uncomfortable. Do you know what this is or how long it normally takes to clear with medication? I landed on your site because someone asked a similar question here, and a doctor referred to the location as posterior pharyngeal wall. Any advice or thoughts?