What to do if i recently had a chest x-ray to look at my lungs. would a pulmonary embolism have shown up?

Unlikely: There are some secondary x-ray signs but usually ct scan or v/q scans are necessary to detect pulmonary clots. Plain chest x-ray can suggest an area with decreased lung markings, density of infarct, or peripheral lung contour abnormalities.

No: There are some classic xray findings for PE, but xray is actually not a good test for diagnosing PE. The best test is a CT Pulmonary Angiogram.