Pain and burning sensation in soles.

My father was  having pain and burning sensation in his soles so we took him to neurologist 7-8 months back and he suggested us to go through some test like MRI, some blood test including test for thyroid and a nerve conduction study test and after the test we were told that my father has a thyroid problem and these were the prescribed medicines (1.Gabapin NT 200,2- Benalgis 100mg,3-Eltroxin 25MCG, 4. ME 12 OD) , so he took these medicines for few months and he was recovering and was not having pain and burning soles so he stop taking the medicine but after few months he was  having the same problem we  again consulted the same doctor and he prescribed to take gabapin nt 400 instead of gabapin nt 200 and all the medicine prescribed earlier were same but it's been 2 months we have consulted the doctor 2-3 times but pain and burning in soles is still there and it gets triggered at night so he is not able to sleep also when he walks and use ice  he get relief for sometime.