Does a calcium score show blocked arteries?

No, that's not what it measures. It shows calcified plaque, which says a lot about your risk. But it can't show whether an artery is narrowed or how well blood reaches your heart. So it's a risk check, not a way to explain symptoms.

A CT with contrast agent (CT coronary angiography) shows narrowing, and a stress test shows blood flow. Your doctor arranges these when there's a medical reason.

If you have chest pain, shortness of breath or palpitations, don't wait for a scan: see a doctor now. For sudden or severe chest pain, call 144.