A patient with a swollen and painful epiglottis has phlegm in the throat, which may be caused by a number of factors. The first thing to confirm is whether the two symptoms are caused by the same disease.
If they are caused by the same disease, it is presumed that an upper respiratory tract infection is more likely.
If they are caused by different factors, other conditions that can cause swollen and painful palate symptoms include mouth ulcers, periodontitis, etc.