They recanalised your LAD, but your EF is only 30% So this could be the reason you get problems, it's low. Your EF should be at least 50% to be normal. When you eat, a substantial amount of blood is directed at your digestive system, causing the heart to work harder. If you do any exertion on top of this, it's not uncommon for angina to set in, for those who have heart disease.
You are young to have problems with your LAD vessel, and I have to ask if you eat a very unhealthy diet or smoke heavily?
I wonder if the LAD was substantially blocked before being recanalised and they are waiting for your left ventricle to recover. Perhaps it would be wise for them to perform a nuclear perfusion scan to evaluate any tissue damage.