HI, thanks for using healthcare magicPost nasal drip
of mucus is most commonly related rhinosinusitis. Rhinosinusitis is inflammation of the nasal and sinus passages.
Allergies are the common cause but there are other causes such as infection, trauma.
Sinusitis can also cause the sensation of fullness or blockage of the ears due to the effect on the eustachian tube which is a tubes that connects the middle ear to the nasopharynx
You may want to consider the use of a decongestant and topical steroid nasal spray
I hope this helps