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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.
Often, it indicates that you have damage to the little hairs inside your ears and they are giving off random signals, which your brain interprets as sound. High blood pressure, high blood sugar or abnormalities in the little bones inside your ear may be a root cause of ear ringing.