Tinnitus is the most common condition that causes a swishing sound in the ears. Tinnitus may also cause a number of other sounds in the ear, including a constant ringing, chirping, rushing, popping, roaring or whistling.
According to the National Institute on Deafness and Other Communication Disorders, about 10 percent of the adult American population experience a form of tinnitus every year. Tinnitus is often one of the first signs of hearing loss and may be a side effect of a number of medications. Working in noisy environments such as construction sites may also cause tinnitus. Other causes include hormonal changes in women, brain tumors and diseases of the heart.