Mrs Smith,
Any changes since yesterday? Did they tell you what was causing your pleuritic chest pain? They must have figured something out - rib fracture? pneumonia? pneumothorax? masses/lesions in rib cage or pleural space .. anything like that. Do you smoke? If so how much? Do you notice any distended veins showing on your stomache? Any changes in your complexion? Facial hair? Any changes in mood? Any pain when you touch certain parts of your stomach? And when you say that you couldn't be pregnant, do you mean you have not had sex since your last menstrual period, or that you did but you just used protection?
I have a few ideas. You don't have to answer all those questions, only ones that you would answer yes too in some way.