Some tightness in chest from last 2 yrs.

Dear doctor once i have feel a heart palpitation and BP about 170/100. And then i have done echo tmt and ecg all are normal and till now i have feel tightness in chest and mold pain and coughing so i have done echo tmt and ecg again in feb and may 21 and also done holter monitoring because i also feel that heart palpitation with in fluctuations rhythm but all result is normal and doctor ruled out that this due to anxiety. And i also have a fear that i will die due to heart attack. And wt is 65 and height is 165cm. And bp is in normal range like 110/75. But now sometimes i feel tightness in my chest i am walking and sometimes not and can follow the rule 150 min regular active in a week. Please sir tell me what is going wrong with me. I am ok or not.