chest pain may be associated with disorders of heart,lung gastrointestinal tract but your mother s past history is suggestive of cardiac cause as there is slightly elevated blood pressure . it should not be due to gastrointestinal tract disorder because she has been taking rabeprazole already. . i would suggest following investigations for your mother- ECG echocardiography. LDL level chest pain in your mother s case is suggestive of acute coronary syndrome that occurs in case of blockage in blood vessels supplying blood to heart. once above mentioned test are done,your cardiologist will treat your mother accordingly. thankyou and takecare.