Hello I appreciate your concern When ECG is normal and it s not a constant problem do chances of blockage is less likely but can t be rule out completely just based on short description. Here I would like further information for better assessment of the condition like Have you experienced swearing or palpitations during an episode of chest pain Do you smoke or consume liquor? Is there any family history of heart attack or heart disease I would advise you get your Blood pressure recorded and in absence of risk factor possibility of blockage can be further evaluated by Echocardiography or TMT testing . Please write back to me with these details so that I will be able to tell you more precisely Best wishes