Why does my heart sometimes does what feels like a hard beat/pump I feel no pain or anything n just did a physical week ago doc said im healthy, activ

Ectopy. This is usually what is felt when your heart throws in an early heart beat. This may be from the upper chamber (atrial premature) or the lower chamber. The early beat is usually not felt, but the next normal beat is more forceful because the heart has more time to fill. Most of these extra beat conditions are quite harmless, but if other symptoms with, see a doc to get evaluated.