Would echo, ekg, stress test, xray, bloodwork rule out any arrhythmia problem such as premature ventricular contraction and paroxysmal atrial fibrillation?

No. Occasional PVCs are normal. Paroxysmal atrial fibrillation by definition is only present some of the time and the tests you list could easily miss this if done while the heart is in normal rhythm. Diagnosis of intermittent arrhythmias can be difficult and frequently requires consultation with a cardiologist subspecialized in electrophysiology, Holter monitor test is frequently used.

Not always... The tests you list may not diagnose an arrhythmia like PVCs or atrial fibrillation. The best way to diagnose these arrhythmias is to have a Holter heart monitor placed. These monitors can be placed for days-weeks and are more likely to diagnose an arrhythmia. So, see your doctor and ask if the heart monitor can be placed!