Thanks foryour query.
There is always a difference in heart rate
at rest and while performing activity.
Since you have a resting heart rate of 90-100 the increase in heart rate till 150 is due to physical activity along with some amount of anxiety
Since your EKG,stress test
,Holter are normal and even Echocardiogram
is normal that means there is no compromise in functioning of your heart.So the increase in heart rate is more likely due to anxiety.I would suggest you to consult your doctor treating you for anxiety and he shall give some medicine to control the heart rate.