How do i differentiate chest tightness from asthma and coronary artery spasms besides using my inhaler or nitro?

Coronary spasm: I don't know how you were diagnosed with coronary spasms. Asthma tightness is very similar. I would look at triggers. What causes the pain to come if it is allergies, humidity, typical asthma triggers it is probably asthma, try your inhaler first. You might try a long acting Nitroglycerin preparation. See your doctor about this.

Chest pain: Chest pain from asthma can be more diffuse whereas coronary artery spasms may be more localized.