trying to figure out whats going on

im 20 years old and at random times my heart rate will rapidly increase and i get shortness of breath and ill get a slight chest pain in my left breast area ill put my hand there and i can feel how fast and how hard my heart it thumping can anyone please tell what might be causing this

[VY_Canis_Majoris]

  Sounds like 'Supraventricular Tachyarrhythmias'. Some meds / enzymes / steroids / Especially weight gain meds could foster this condition. On feels light headed as the palpitations occur.

I suggest you get a holter monitor test to confirm this. I don't thing its anyting too serious seen as though you 're pretty young. This can be easily treated but you might have to take the meds for a long period.

Good luck ...