What can be the cause of constant ringing in my ears?

Tinnitus: Chronic tinnitus has many causes, but commonly is associated with damage to the inner ear and/or associated hearing loss, and the brain's method of compensating for this inner ear damage / hearing loss. You should have your hearing tested by an audiologist and see an ENT to make sure nothing else is going on.

Usually hearing loss: The most common cause of tinnitus is hearing loss. Tinnitus can also be caused by ear injuries, medications, stress, jaw spasm and many other reasons.