Troponin would show if you have any heart damage, so looks like you don’t and aren’t having a heart attack right now. ECG is also to check how your heart is.
Neither of these will indicate if you have a “blockage” issue.
As an ex-smoker myself who knows the type of pain you are describing I would suspect significant plaque in your coronary arteries.
I would reccommend a CT Coronary Angiogram (dye injected and then arteries scanned), and also getting a Coronary Calcium Score.
Calcium Scores are really only useful as a marker to check against a later Calcium Score to note change, so aren’t used much now because whilst you ideally want a zero calcium score, you can have a zero calcium score when you have lots of dangerous soft plaque that doesn’t have any calcium in it.
When it comes to plaque there are two basic types; plaque starts off soft (this is dangerous plaque) then it gets calcified and becomes harder. When hard it is stable and is much safer. It’s softer plaque that can erupt into an artery, clot and result in a heart attack or stroke.
With modern CT Coronary Angiogram they should be able to see soft plaque as well as hard. If you have significant soft plaque and make positive lifestyle changes (such as quitting sugar and flour) to help stabilise the soft plaque, your Calcium Score will go up but your risk in reality will go down.
You could also, perhaps more cost-effectively try to get a CIMT (Carotid Intima Media Thickness) ultrasound test - done on your neck. This is less invasive and if you have plaque/calcium in your neck arteries then you WILL have it in your heart arteries.