I'm in the same boat as you are: familial high cholesterol.
No, arterial spasm will NOT show on ECG.
I complained for years about
chest pain on exertion, nothing showed of ECG, nothing showed on stress test or cardiac ultrasound, not anything on holter monitoring, and then I had a small heart attack. It was triggered by eating a bowl of cereal which started gastric reflux, which triggered tachycardia, which triggered a small plaque rupture and a pinpoint narrowing of a cardiac artery. You can research the phenomenon - cardio-esophageal reflex. I had seen three docs and nobody believed me that something was wrong. That's what I got for being a woman. I was told I was just out of shape, although I do the maintenance for a small summer camp.
When the stent I was given didn't cure my chest pain, and even though I supposedly passed another stress test, I went to another cardiologist and said the magic words: "I think I'm going to have another heart attack." I got another angiogram and needed another stent. Now I feel much better, in that department.
See someone else and keep on insisting.