Lately i've been experiencing very short, rapid heart beats with the finally one being very painful. after this i get sharp pains in abdomen. why?

Arrythmia ?: Not sure about abdominal symptoms but other symptoms sound like possible arrythmia. Talk to your physician about further evaluation which may include a holter or event monitor & echocardiogram.

Holter Monitor: You should get a holter monitor to see if you can capture these rapid heart beats. I can't explain the abdominal pain with the small rapid heart beats.