Hi friend,
Welcome to Health Care Magic
Irregular heart beats need to be DOCUMENTED by ElectroCardioGram (EKG).   Standard ECG records the electrical activity of the heart, for a few seconds. It can detect the 
arrhythmia occurring during that time only.  If the episode occurs randomly or precipitated by a specific activity like exercise, one needs Holter or event monitor.  Holter records for days; Event monitor for weeks / Holter records continuously / Event monitor only at certain times .  
You have not stated your age, gender, personal habits, family history or co-morbidities
Anaemia / Anxiety / Alcohol / Tobacco (smoking) / Caffeine (too much coffee, cola) / Medicines like 
Phenylephrine used for ‘cold’; 
Salbutamol used for asthma and so on are common causes...
Fever / Thyroid / Vitamin D, calcium and 
magnesium may all have a role... / Illicit ‘drugs’ like 
Amphetamine are notorious to cause abnormal beats /  At times, abnormal nerve paths in the heart (bypass tracts) are responsible! 
See your doctor...
Take care
Wishing speedy recovery
God bless
Good luck