Burning sensation in feet. Difficulty walking or standing. What to do?

Hello Doctor, This is regarding my mother s health. She is of 65 years old. She doesn t have any B.P. , diabetics as per her every 3 months checkup . But she is very badly suffering with pricking sensation, burning and pinching in her both feet . She is suffering it from the last 4 years . But sometimes the pain is unbearable throughout the day . She cannot stand or walk for more time. Otherthan this she has no other complaints. Please please kindly tell me the reason for this pain and also the proper specialist for this problem . They stay in a town. She could show to a specialist in Vizag in Andhra Pradesh in India. Please kindly tell me your advise . We are very greatful to you.