Do you hear a ringing, roaring, clicking or hissing sound in your ears? Do you hear this sound often or all the time? Does the sound bother you? If you answer is yes, you might have tinnitus. Millions of people in the U.S. have tinnitus. People with severe tinnitus may have trouble hearing, working or even sleeping. Causes of tinnitus include hearing loss, exposure to loud noises or medicines you may be taking for a different problem. Tinnitus may also be a symptom of other health problems, such as allergies, high or low blood pressure, tumors and problems in the heart, blood vessels, jaw and neck. Treatment depends on the cause. Treatments may include hearing aids, sound-masking devices, medicines and ways to learn how to cope with the noise.