Diziness and usteadiness. Be the reason?

I had giddiness one month back all of sudden, went  to ER and suspected gas problemsgit medication.Giddiness was controlled, after that I started having dizziness issues while moving head ,unsteadiness while standing still and talking.My eyes also started to pain on top under eyebrows.While lying flat or sitting in a chair I don't have any issues.I have consulted neurologist and had brain MRI and it was normal study i consulted eye specialist and visited ent also.Now as per suggestion from General physician I am having some medicines related to releive the pressure in the neck as the suspicion was it might be because of neck posture.Any suggestions on diagnosis? My b12 level is 178 could this also be the reason?