Hello The shortness of breath and cough caused mostly by an allergic reaction. The infection, it s also a frequent cause, but it s associated mostly with fever if it s a bacterial infection. For the viral infection normally it should be gone in 7 days, even without a specific treatment. Since your x-ray is normal, it s mostly an allergic reaction. You should recognize the possible substance that causes an allergic reaction to you like cat s hair, pollen, some food..... You should have an environmental control to avoid new episodes in the future. I suggest that you trust your doctor and consult him if you have an exacerbation of symptoms or you have any new symptom like skin rash for example. Hope I answered your question Wish you a speedy recovery Best regards Dr. Noor Farid