Hello,
Burning sensation in food pipe that is 
esophagitis or retrosternal burning can be due to the medications that you have taken for a long time and/or due to GERD that is 
gastroesophageal reflux disease.
This can be diagnosed by the following:
Upper GI endoscopy and other tests to determine the cause and plan for management in the following way:
• Get started on a PPI like 
Omeprazole and continue as per the need.
• Gastric ph measurement and manometry.
• Antacids to neutralize the acidity, given every three hourly.
• Motility regulator like 
Domperidone.
• 
Constipation and other problems can increase the existing problems. 
• Stress and anxiety can increase the problems as are the hot and spicy, oily foods which you have to stop strictly.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. T Chandrakant