Why do my head and ears always buzz~~~~~ when I'm quiet?

This phenomenon is very common. It has both physiological causes—related to “human nature”—and pathological causes—resulting from “external factors or illness.”

1. Human Nature: Physiological Tinnitus (“Background Noise” Phenomenon)
   The human auditory system is extremely sensitive. When the external environment suddenly becomes completely silent, the auditory nerves do not receive sufficient external signals. To detect sound, the brain automatically increases the “sensitivity” of the auditory system. At this moment, what you actually hear are the sounds of your body’s internal processes—such as the flow of blood through tiny blood vessels in the ear, the faint sounds of muscle contractions, or even the faint electrical signals spontaneously generated by auditory nerve cells.
   The musician John Cage once entered an “absolute silence chamber” (anechoic chamber) at Harvard University. He had expected to experience absolute silence, but instead clearly heard two distinct sounds: one low-frequency (the sound of blood circulation) and one high-frequency (the sound of the nervous system at work). This demonstrates that as long as the human body is functioning, absolute “silence” does not exist.
2. Caused by external forces or physical factors: Tinnitus resulting from pathological conditions or the external environment
   If this “buzzing” sound can be heard even in noisy daytime environments, or if it is loud enough to be distracting, it may be a warning sign of external injury or a physical issue:
   Noise-induced hearing loss (the most common external cause): Frequently listening to loud music through headphones, attending a recent concert or visiting a noisy bar, or working long-term in a noisy environment can damage the extremely fragile “hair cells” in the inner ear. Once these hair cells are damaged, they continue to send erroneous electrical signals to the brain even in the absence of sound, and the brain interprets these as a persistent “buzzing” sound.
   Stress and Fatigue (Common in Modern People): Chronic late nights, sleep deprivation, severe mental stress, or anxiety can lead to autonomic nervous system dysfunction and insufficient blood supply to the inner ear’s microcirculation, which can easily trigger tinnitus and brain-related ringing.
   Disorders of the Ear and Surrounding Organs: Conditions such as earwax blockage (cerumen impaction), otitis media, or temporomandibular joint disorder (TMJ) can alter internal ear pressure or sound conduction, resulting in ringing.
   Systemic issues: High blood pressure, cervical spondylosis, or the use of certain medications with ototoxic side effects may also cause tinnitus.
   If you only hear a slight “buzzing” sound when you’re quiet, that’s your body’s natural “ “background noise”—a natural phenomenon in humans. You can simply play some white noise (such as the sound of rain) or soft music to mask it; however, if it persists, grows louder, or is accompanied by hearing loss or dizziness, it is highly likely caused by external factors or physical fatigue/disease, and you should see an ENT specialist promptly.