Yes you can pass a stress test and still have a blockage of your arteries.
A stress test can only really detect if the arteries are blocked 70 percent or more.
If your arteries are not blocked at least 70 percent or more then you may still have an artery blockage even though you passed the stress test.
A stress test is a good test though that can help detect blockages but the only really true and 100 percent way to detect a blockage in your arteries is to have a Electrocardiogram, Chest X Ray, MRI or PET scanning and a Cholesterol Screening.
If you need your arteries cleaned then they can usually clean your arteries through a surgical procedure and may even need to put in artery stents to prevent a blockage.