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Hi Sue, The ringing in the ears is called Tinnitus. It can be a side effect of medications (check what you are taking) or for me, it can also be a sign that a migraine is on the way. It could also mean a number of many other things, depending on other symptoms you may have.
Damage to your eardrums or the tiny bones in your middle ear can also interfere with the proper conduction of sound. Tumors in the ear or on the auditory nerve may also cause ringing in the ears. Exposure to very loud sounds on a regular basis can cause tinnitus in some people. Those who use jackhammers, chainsaws, or other heavy equipment are more likely to have tinnitus.