Hi, Hearing a fizzy sound in your skull is called tinnitus. Feeling lightheaded is called dizziness. Difficulty balancing is called ataxia. Tinnitus, dizziness and ataxia are symptoms of vestibular problem in your ear. Human ear has 3 parts called external, middle and inner ear. Inner ear has 2 parts called cochlea and vestibule. Any problem with vestibule of inner ear causes the above symptoms. But please keep in mind that they can be caused by .some conditions that are self limiting like vestibular neuronitis (swelling of a nerve called vestibular nerve supplying your inner ear) and also by certain dreadly tumours like acoustic neuroma. So, just visit your ENT specialist to get some hearing tests done to see if everything is normal with your ear. He also might suggest CT scan of your head to rule out tumours. He might refer you to a neurologist if ENT test turn out to be normal. Please dont neglect your condition. Try to visit a ENT doctor as soon as possible.