An angiogram is the gold standard - against which all other tests are compared... A normal angio excludes mechanical obstruction but not spasm causing chest pain
(Prinzmetal variant) - probably, they might have done provocative tests to rule out - have it clarified.
The cardiologist has suspected on initial encounter - investigations have clarified.
Of course a cardiologist is the better person under the circumstances - he is also basically an internist - further trained and specialised in one speciality.
Age does not exclude any disease - statistically, some are common ia a particular age, gender and so on. In an individual instance, that is not a major consideration - one sees the overall picture....
You have a third opinion! I will go for from a cardiologist