I am sorry to hear that you have swelling behind you ear, under your armpit, and that you lost your hearing in that ear. I am happy to give you some information about your ears and my thoughts about what might be going on, but ultimately I am going to recommend that you make an appointment to be evaluated by an ENT (Ear Nose Throat) physician. They will be able to examine you and take more of a history to give you a more accurate answer for what is actually going on (rather than my educated guessing). They will likely order an audiogram which is a hearing test. This will give valuable information about what is going on with your ear and your hearing. It is possible that you are suffering from something called sudden sensorineural hearing loss, which is a condition that is thought to be secondary to a viral infection. This condition is usually associated with unilateral hearing loss, and a pressure sensation in the affected ear, sometimes also associated with tinnitus (ringing in the ear). It does not however cause actual inflammation of the ear, nor would it cause swelling in your neck. You could have an infection in your ear (such as otitis media, or otitis externa) which could cause inflammation of the lymph nodes in your neck (but not under your armpit) and hearing loss. An ENT will be able to examine your ear and tell you if it looks normal or not. Sudden sensorineural hearing loss generally has a normal ear exam. I wish you all the best.