I Am Unable To Walk Continuously. I Am Getting Chest

I am unable to walk continuously. I am getting chest tightness. Then I have to stand for 5 to 7 minutes before start walking further. It is repeated to cover distance. No breathing problem. Hypertension managed well with Telmika 20 tab 1 in the night. Normal diet. No outside food except 1 or 2 tea in the office. I am aged 55 years. Sleep normal.