Heart rate when resting should be in the range 60-80 beats per minute. It normally rises during the physical work. You are probably experiencing some kind of tachycardia but only ECG-test can say which type. 24 hours "holter"-monitoring can be also requested.
Can you tell me what your ECG-report says?
Echo is used to evaluate heart's structure (walls, cavities, valves, blood-dynamic etc.) and to find the source of that murmur.
Can you appeal to some cardiologist if your doctor doesn't understand?