Hello and thank you for using HCM.I carefully read your question and understand your concern. But you should not worry,its nothing serious. As you describe, my opinion is that it might be a rhythm issue. Someone can feel strong and fast heart beats for different reasons. It may be a simple sinus tachycardia. This means that the heart is beating faster than 100 beats for minute. Its normal range in a resting condition is between 60-100 beats for minute. When it goes up you may feel a strong heart beat in your chest and a sensation like your body is beating too. Another reason for this sensation might be what we call an ekstrasystol.This are electrical heart impulses that generates in some parts of heart different from normal sinus rhythm.This generate an escaped beat that the person feels like jumping ore bumping .It gives the sensation like a beat is skipping,may experience palpitations or an anxiety sensation that your daughter explains like trembling .This extrasistoles may happen from different reasons from simple emotional stress to other pathologies like anemia,hyperthyroidism ect. So, my opinion as cardiologist is that you have nothing to worry. It is just a simple episode and it is quite normal in younger ages. Only if this symptoms persist and begins to interfere the daily live, if I was your treating doctor I will recommend some examinations like a blood analysis to exclude anemia,the thyroid hormones,an electrocardiogram, echo cardiography and of course a holter monitoring.This will help us to document and see what happens with heart rhythm. At meantime I will recommend your daughter to avoid coffee,caffeine products because they rise heart frequency and extrasistolic beats. I encourage her to have physical training because sometimes it helps in reducing extrasistoles,tachycardia, even making them disappear. Wish I was helpful.Take good care.Best regards