What does angina feel like?

I'm 75 years old, male, fairly fit, diagnosed with Coronary Artery Calcification this fall. According to all the tests including spect and pet my perfusion and flow are good but there is significant calcium in LM and LAD.

This all began because i had an episode this summer walking fast up a hill for a km or so. It felt like pressure in my left chest and arm. I stopped for 30 seconds and it went away so i went up the rest of the hill at a slower pace and was fine.

Now i'm on a statin and a beta blocker and carrying around a nitro puffer.

Now my question: When we go for a walk, after maybe 15 minutes I will start to feel a heaviness in my left arm like a hand on my shoulder and in my left arm and sometimes the neck. If i stop it fades. I have tried puffing the nitro when it happens and also before the walk but it's not clear whether it helps or not. The whole thing is kind of vague and diffuse. Is angina more definite than this? Either with or without the puffer I have not experienced what i did on the hill this summer.

Thanks for any relevant experience.