Sudden hearing loss in one ear over a short period is often called sudden sensorineural hearing loss, and it can be caused by viral infections, inflammation of the inner ear, reduced blood flow, ear fluid buildup, or, rarely, nerve-related problems; sometimes, no clear cause is found. Since your symptoms started 7 days ago, it is important to understand that early treatment (usually with steroids) gives the best chance of recovery, so this condition should be treated as urgent, even if there is no pain. Some people may also notice ringing in the ear, a feeling of fullness, or dizziness along with hearing loss. While minor causes like earwax blockage can also reduce hearing, a sudden onset should not be ignored. You should seek medical evaluation from an ENT specialist as soon as possible for hearing tests and appropriate treatment, as delaying care may reduce the chances of full recovery.