If i had a heart ultrasound and ecg would they show many major problems?

Might or might not: Heart ultrasound (echocardiogram) looks primarily at the anatomy of the heart and its function. It may detect valve problems, contractility issues or other structural abnormalities. It may not be able to detect any arrhythmias (except for possible atrial fibrilation) or tell you about presence of coronary artery disease. Ecg on the other hand may not be able to give you ample info on the anatomy.

Data: The combination of ECG and cardiac ultrasound would give evidence for state of cardiac rhythm and cardiac anatomy and function. It is a combination of many of the things we want to know about someones heart.