Suggest Treatment For Lightheadedness

Hi,

For 9 years, I've had a constant lightheadedness and pressure in my head. The lightheadedness i so bad that I need a wheelchair just to get around because I'm afraid of falling and I have before. I've tried numerous medicines with no relief. I'm seeing a neurologist, neurosurgeon, ent, physchiatrist, and a therapist and nothing seems to help. the tests come back normal. any suggestions?