How could I relieve asthma related chest discomfort until the morning when I can see my doctor?

Albuterol. Everyone who has asthma should have albuterol or xopenex (levalbuterol) available to them at all times. If you feel tight, you should use it. Discuss with your doctor, but you can usually use up to three doses back to back to relieve your symptoms. If after three doses you are no better, you should go immediately to the emergency room. Everyone with asthma should have a rescue plan like this worked out.
More albuterol is OK. Dr. Mcghee's remarks are correct. The danger of uncontrolled asthma far outweighs the risk of extra puffs of albuterol or xopenex (levalbuterol). To place that risk in perspective 1 tsp of albuterol syrup, the dose for a child of 40 lbs is equal to 21-22 puffs of albuterol. The message is take more albuterol if you need to but get medical attention as soon as possible.