Otalgia or Outer Ear Infection: Given the location of the pain (anterior to the right ear) and the symptom of decreased hearing, an outer ear infection or otalgia (ear pain) is a plausible diagnosis. This condition is relatively common and can cause significant discomfort and temporary hearing impairment.

Middle Ear Infection (Otitis Media): This condition can cause pain in the ear, decreased hearing, and is often accompanied by other symptoms such as fever and a feeling of fullness in the ear. The proximity of the pain to the ear and the hearing loss make this a likely consideration.
Temporomandibular Joint (TMJ) Disorder: TMJ disorders can cause pain in the jaw area that radiates to the ear, as well as clicking or popping sounds when moving the jaw. While the primary complaint is neck pain, the location anterior to the ear and decreased hearing could be related to TMJ dysfunction affecting the Eustachian tube or causing referred pain.
Cervical Spondylosis or Cervical Strain: Although the pain is described as being anterior to the ear, cervical spine issues can refer pain to various areas of the neck and potentially cause discomfort that might be perceived near the ear. Decreased hearing could be less directly related but might be considered if the patient has a history of cervical spine disease.

Mastoiditis: An infection of the mastoid bone in the skull, located behind the ear. It's a serious condition that can arise from untreated or inadequately treated otitis media. Symptoms can include pain behind the ear, fever, and hearing loss. Given the potential severity and complications of mastoiditis, it's crucial not to miss this diagnosis.
Petrous Apicitis: A rare but serious infection of the petrous part of the temporal bone. It can cause severe pain, hearing loss, and other neurological symptoms. Although rare, the potential for serious complications makes it a "do not miss" diagnosis.
Cerebellar Stroke or Hemorrhage: While less likely given the specific symptoms, any sudden onset of severe headache, neck pain, or neurological deficits could indicate a cerebellar stroke or hemorrhage. The decreased hearing could be a red flag for a more central cause, especially if accompanied by other neurological symptoms.

Ramsay Hunt Syndrome Type 2: Caused by the varicella-zoster virus, this condition can lead to facial paralysis, ear pain, and sometimes hearing loss. It's less common but should be considered in the differential diagnosis, especially if the patient has a rash or other neurological symptoms.
Eagle Syndrome: Characterized by an elongated styloid process or calcified stylohyoid ligament, which can cause ear pain, facial pain, and sometimes hearing disturbances due to the proximity of these structures to the ear and the nerves involved. It's a rare condition but could explain the combination of symptoms if other diagnoses are ruled out.