Hi, Welcome to health care magic, It could be because of bronchitis (allergic or infective) or esophagitis or acute gastritis some times etc. Here,if your father s heart evaluation has come to normal then there is no need to be worried much. He may undergo routine blood count,ESR with X- ray chest and pulmonary function test if these tests had not done earlier. He might require antibiotics (quinolones or macrolides or amoxillin with clavulanic acid) with antiallergic drugs like antihistamines,analgesics on SOS basis and antacids like pantoprazole with digene syrup 2 TSF three times day. He must consult your physician if the chest pain remains constant even after symptomatic treatment. Regards,