Does a normal ekg and ultasound, etc. rule out heart problem? when i am sitting down for a while and i rapidly get up i feel like my heart flutters?

Those normal tests (EKG and echocardiogram) do not rule out all heart diseases, otherwise a cardiologist does not need an extra 3 years of fellowship in cardiology on top of 3 years of internal medicine training. Your symptom may not be abnormal at all if you are sensitive to a sudden high heart rate but a thorough physical exam to rule out postural orthostatic tachycardia syndrome is recommended.

EKG and ultrasound do help in diagnosing heart disease, however they are not always diagnostic. Your symptoms suggest a postural maladjustment and lifestyle modifications would be first to try( physical exercise, proper hydration, reducing caffeine/alcohol/marijuana if applicable). Talking to your doc in case symptoms do not abate will be next.