I agree that you have tinnitus. While there are several causes for tinnitus including hypertension, high cholesterol, autoimmune disease certain infections etc, in general no cause for the tinnitus is found. Your plan to see a neurologist is a good one. If you have normal brain CT and MRIs it is highly unlikely that you have brain disease. Getting 2 or 3 CTs or MRI of the head will not predispose you to brain cancer.