Light Headedness and Brain Fog.

I am a 32 year old male experiencing persistent light headedness, brain fog, blurred vision, and neck stiffness for the past 2 years. The symptoms are present almost daily and significantly affect my quality of life. I have consulted multiple neurologists, a cardiologist, and an orthopaedic specialist. MRI scans and other investigations have been reported as normal. I continue to experience these symptoms despite normal test results and no clear diagnosis. Could this be related to a vestibular disorder, cervical spine dysfunction, TMJ/jaw clenching, autonomic dysfunction, posture related issues, or another underlying condition? What further investigations or specialist consultations would you recommend?