Hello. Thanks for asking form HCM. I can understand your concern. It is good that you are getting relief in headache. This ringing sound without actual sound is known as Tinnitus. It can occur after lumbar puncture after excessive fluid drainage. Most probable cause is stretching of hearing nerve after over drainage. It usually manifests more in silent surrounding as noise masks it, thats why you are hearing it more while going for sleep/on lying down. It usually subsides on its own. But get more relief, you can follow few tips : Maintain adequate hydration by drinking 2.5 to 3 litre of fluids daily. : Keep your head at lower level than chest and foot. You can do it by elevating foot end of your bed. : You can take betahistine or Cinnarizine tablet after proper prescription. It will relieve light headless and sometimes tinnitus also. : If still no relief, consult Ear specialist to rule out ear disease as the cause. Further management will be decided after diagnosing actual disease. Ear will be examined by audiometry to find out deafness. Hope it will help you. Take care. Thanks.