Hi... Welcome to healthcare magic... According to your complain your daughter has problem breathing difficulties and more mucus that may be because of respiratory infection or allergy. Respiratory irritation cause more cough and breathing problems. Consult a pulmonologist for further diagnosis. Auscaltation of respiratory sound helpful in diagnosis. Complete blood cell count and microscopic examination for further diagnosis. Peak flow meter use to note a respiratory capacity. Sputum culture test for further information. Chest X ray can done if needed for diagnosis. Proper history and physical examination give exact idea about disease. Steam inhalation helpful to you.. Start a treatment according to cause. I hope my guidance helpful to you.. Take care. Thank you.