Referred otalgia from temporomandibular joint (TMJ) disorder or dental issue: Pain in the ear that worsens with swallowing, especially liquids, can be referred from the TMJ or dental issues due to shared nerve pathways. The act of swallowing can exacerbate TMJ pain, which is then referred to the ear.

Acute otitis externa (swimmer's ear): This condition can cause ear pain that worsens with swallowing due to the movement of the jaw and the eustachian tube, which can irritate an already inflamed external ear canal.
Eustachian tube dysfunction: Problems with the eustachian tube, which connects the middle ear to the back of the nose and throat, can lead to ear pain that worsens with swallowing or drinking, as these actions can increase pressure changes in the ear.
Strep throat or tonsillitis: Infections in the throat can cause referred pain to the ear, especially if the infection involves the eustachian tube or if there is significant lymphadenopathy (swollen lymph nodes) in the neck.

Malignancy (e.g., nasopharyngeal carcinoma): Although rare, cancers in the head and neck region can cause ear pain, especially if they involve the eustachian tube or surrounding structures. The worsening of pain with swallowing could indicate involvement of the throat or esophagus.
Lymphoma: Similar to other malignancies, lymphoma can cause ear pain if it involves the lymph nodes in the neck or the eustachian tube.
Temporal arteritis: This condition, which involves inflammation of the blood vessels, can cause severe headaches and jaw claudication (pain when chewing), but it can also lead to ear pain, especially if the vessels supplying the ear are involved.

Ramsay Hunt syndrome type 2 (geniculate neuralgia): This condition, caused by the varicella-zoster virus, can lead to ear pain and is associated with herpes zoster infection of the geniculate ganglion.
Glossopharyngeal neuralgia: A rare condition characterized by recurrent episodes of severe pain in the tongue, throat, ear, and area of the jaw, triggered by swallowing or other actions.
Eagle syndrome (stylalgia): Caused by an elongated or calcified styloid process, this condition can lead to ear pain, especially with swallowing, due to irritation of the surrounding nerves and tissues.