Eustachian Tube Dysfunction: This condition is a common cause of ear discomfort and is often related to changes in air pressure, allergies, or upper respiratory infections. The symptoms can include a feeling of fullness or pressure in the ears, hearing loss, and discomfort, which can be bilateral.

Otitis Media with Eustachian Tube Dysfunction: This condition involves inflammation of the middle ear and can be caused by bacterial or viral infections. It often presents with ear pain, fever, and sometimes discharge.
Allergic Rhinitis: Allergies can cause Eustachian tube dysfunction leading to ear discomfort. Symptoms include sneezing, runny nose, and itchy eyes, in addition to ear fullness.
Upper Respiratory Tract Infection (URTI): Common colds or flu can lead to Eustachian tube dysfunction and cause ear discomfort among other symptoms like cough, sore throat, and runny nose.

Mastoiditis: Although rare, mastoiditis is a serious infection of the mastoid bone in the skull, located behind the ear. It can arise from untreated or inadequately treated otitis media and requires prompt medical attention.
Petrous Apicitis: This is a rare but serious infection of the petrous part of the temporal bone. It can cause severe ear pain, fever, and neurological symptoms.
Lymphoma or Other Malignancies: Though uncommon, certain cancers can present with ear symptoms, including discomfort, due to involvement of the Eustachian tube or surrounding structures.

Relapsing Polychondritis: A rare autoimmune disorder that can cause cartilage inflammation, including the cartilage in the ears, leading to discomfort and other ear symptoms.
Temporal Bone Fracture: Trauma to the temporal bone can cause ear discomfort among other symptoms like hearing loss and vertigo.
Paget's Disease of Bone: A chronic bone disorder that can affect the temporal bone, leading to hearing loss and ear discomfort, though it's more common in older adults.