Final answer:
The diagnosis is stable angina and the treatment involves relieving symptoms and slowing the progression of atherosclerosis.
Step-by-step explanation:
The diagnosis for the patient described is angina, specifically stable angina. Stable angina is characterized by chest pain or pressure that is precipitated by exertion and improves quickly with rest or the administration of nitroglycerin. The treatment for stable angina involves relieving the symptoms and slowing the progression of underlying atherosclerosis. Immediate treatments for chest pain due to angina include administering supplemental oxygen, aspirin, and sublingual nitroglycerin to improve blood flow.