Hi, sounds like good advice, and sounds like you will make the effort to act on this advice. But still, let me just add a few comments.
With flying, the stress should be just part of the job...something that you expect to feel; almost invigorating. However, explained in simplistic terms, Nicotine has a way of turning ‘good stress' into a very destructive kind of stress. This in turn will affect your overall health by directly affecting your immune system.
By this means, smoking could alter your ‘body chemistry' very significantly.
There is now very solid evidence showing that stress gives a short term boost to the immune system, but then causes a long term suppression of this vital function. Your overall health can suffer significantly as the result of the wrong stress reaction.
It is your clear duty to check out the chest pain. The odds are that you will be ok, and at your age, in one year from now, you could be clear of all smoking side effects and be practicing a good aerobic sport. It's up to you. Good luck.