Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

Experts believe that tinnitus is associated with neural (brain and nerve) injuries that affect the auditory pathway and therefore someone’s ability to hear sounds. (10) Most of the time, tinnitus is a result of a disorder that affects parts of either the outer, inner or middle ear. The good news is that the majority of cases are not linked to any serious illness, although some cases are.
Smoking. Contrary to popular belief, there are some external irritants that can cause tinnitus. For example, Nicotine has been proven to be an irritant that can cause someone to develop a ringing in their ears. Smokers may find that their chances of developing the condition may be higher than someone who is a non-smoker. If you’re suffering from tinnitus right now, and you’re a smoker, please quit as soon as possible. If that’s just not an option for you right now, be sure to at least pick up an over the counter tinnitus treatment that will dramatically reduce the ringing in your ears.
Supporting the idea that central reorganization is overestimated as "the" cause of tinnitus, a recent study by Wineland et al showed no changes in central connectivity of auditory cortex or other key cortical regions (Wineland et al, 2012). Considering other parts of the brain, Ueyama et al (2013) reported that there was increased fMRI activity in the bilateral rectus gyri, as well as cingulate gyri correlating with distress. Loudness was correlated with values in the thalamus, bilateral hippocampus and left caudate. In other words, the changes in the brain associated with tinnitus seem to be associated with emotional reaction (e.g. cingulate), and input systems (e.g. thalamus). There are a few areas whose role is not so obvious (e.g. caudate). This makes a more sense than the Wineland result, but of course, they were measuring different things. MRI studies related to audition or dizziness must be interpreted with great caution as the magnetic field of the MRI stimulates the inner ear, and because MRI scanners are noisy.
Before long, you’re both mentally and physically stimulated in ways that make it even harder to relax and fall asleep. Like any other form of anxiety, stress about falling asleep creates mental arousal, bringing your brain to alertness. And it also creates physical arousal, raising heart rate and body temperature. This kind of anxiety can lead to behaviors that further undermine sleep, including:
For some people, the jarring motion of brisk walking can produce what is called a seismic effect which causes movement in the small bones or contractions in the muscles of the middle ear space. You can experiment to find out if this is the cause by walking slowly and smoothly to see if the clicking is present. Then, try walking quickly and with a lot of motion to see if you hear the clicking. You can also test for the seismic effect by moving your head up and down quickly. 
Widex employs fractal tone technology, so that the sounds you hear are predictable but not repeating. Your audiologist can choose between an assortment of “musical tones” known as “Zen styles,” which are random and chime-like. Your audiologist can adjust the tones’ pitch, tempo, and volume. If employed correctly, Widex Zen Therapy can help re-wire your brain and make your tinnitus less noticeable.
Tinnitus is the hearing of sound when no external sound is present.[1] While often described as a ringing, it may also sound like a clicking, hiss or roaring.[2] Rarely, unclear voices or music are heard.[3] The sound may be soft or loud, low pitched or high pitched and appear to be coming from one ear or both.[2] Most of the time, it comes on gradually.[3] In some people, the sound causes depression or anxiety and can interfere with concentration.[2]
Though the exact cause of tinnitus — as in the specific mechanism that creates these phantom sounds in some people — remains unknown, contributing factors and triggers have been identified. Excessive exposure to loud noise is often a factor because of the damage done to your auditory system. Tinnitus may also result from jaw-joint dysfunction (e.g., teeth grinding, temporomandibular joint disorder) or chronic neck muscle strain.

Loud noise exposure: Being exposed to occupational loud noise on a regular basis from heavy equipment, chain saws or firearms is a common cause of tinnitus. However, even if you don’t work in a noisy environment, you can still suffer the effects of noise exposure by listening to loud music through headphones, attending live music performances frequently and engaging in noisy hobbies.