Thanks for your query.
First of all i would inform you that do not rely on description written on ECG, always seek expert opinion to interpret ECG.
Chest tightness/Pain radiating to arm or neck is classical sign of Myocardial infarction
, you may have prior angina attacks. Along with ECG you needed to perform cardiac markers to exclude cardiac ischemia or infarct. Some trivial infarcts may no bother but should be taken serious to avoid future problems. However low QRS alone do not indicate anterior infarct, it should have been checked with other cardiac markers like troponin. there are many other causes of low voltage QRS like emphysema, COPD, pericardial effusion
, pleural effusion
, edema, fat (obesity), physiologic variant, or cardiomyopathy
Left atrial enlargement is suspected when P wave on ECG to become broadened and often substantially notched or second part of P wave is high voltage. Left atrial enlargement indicate valvular disease and may be caused by hypertension
Stress can cause palpitation and changes in ECG, so sort out it.
Revisit your doctor to rule out any cardiac disease, he may advise labs like RBS,cholestrol level, ECG, X-ray, Echocardiograph or cardiac perfusion Scan.
Hope it helps.