I have been experiencing high heart beating to a point where i cannot sleep. i feel it especially after i eat. going fast for hours! pain left arm?

See a doctor: immediately to see if you have an irregular heartbeat called atrial fibrillation, You can go to ER.

Palpitations: few persons can have palpitations like what you are describing because the electrical system of the heart has different pathways then usual. This needs to be checked by a heart doctor to avoid your heart getting fast to a point of being dizzy or even passing out. Meanwhile avoid coffee,tea, eating late at night and having food that can potentially cause you acid reflux such as tomato, chocolate.