Tinnitus refers to a ringing or other noise in the ears. It may affect one or both ears. In most cases, the sound is subjective. This means only you can hear the ringing. You may hear it even when your environment is silent.
Around 15 to 20 percent of humans have this condition.  While it can affect anyone, it is more common in adults. Tinnitus is not a disease by itself but a symptom caused by other conditions. This article discusses the symptoms of tinnitus and the possible causes of this problem.
Symptoms of Tinnitus
The main sign of tinnitus is a ringing noise in one or both ears in the absence of external stimulation. Other sounds you may hear instead of this ringing noise include: 
These sounds may be dull or loud enough to distract you from being able to perform a task or listen to external sound.