HI, thanks for using healthcare magic
Angina means that blood supply to parts of the heart is reduced.
During activity, when the heart needs more blood, the pain may be felt.
If the angina worsens due to increased blockage of the blood vessels, then angina would progress to occurring at rest.
It can cause
chest pain and other symptoms, if it is not treated, then it can be severe.
It would be best to use your medication as prescribed. The medication given would help to dilate (widen) the blood vessels and therefore increase blood supply to the heart.
In terms of side effects, these may or may not occur but include
dizziness,
headaches, lightheaded sensation, weakness , palpitations.
I hope this helps