Dear Sir/ Madam
Thanks for your query to us.
1. The lightheadedness
can have multiple causes in your case like medications, low pumping of heart and neurological abnormalities.
2. Normally we tend to graft as many stenosis as possible to achieve near complete revascularization. However only your cardiologist can explain about the decision taken at that time.
3. The new tightness of chest may be due to progression of earlier untackled disease or may be a new lesion or a stenosis of the graft itself. This should be looked into urgently. please see your cardiologist.