Discomfort (like breatlessness and like my heart has stopped beating)in chest while sleeping on the right side.should i be worried?

Maybe: The symptoms sound like pvcs. The early ventricular beat is followed by a pause then the following beat is accentuated and palpable. This may be nothing and your only noticing it at night because its quite and no other distractions. Can be a symptom related to sleep apnea , a life threatening condition. A full work up is needed. Holter, echo, stress test , labs and possible sleep study.