What Causes Shortness Of Breath And Chest Pain Upon Walking?

hi my husband is having trouble with chest pains he s keeps getting heavy aching in his chest and shortness of breath some times with the slightest of movement ,he cant walk more than app. 20 yrds before we have to stop this is walking at a steady pace he also gets a strange feeling in his face and arms could you tell me what it might be he has nt seen a doctor yet thankyou