Care of a Child with Recurrent Cough

1.My baby was born prematurely. She weighed 1.8 kg at birth. Now she is 5 months old. She gets to cough very often. What tests do I need to get done?
2. My 1-year-old son gets a cough very often. What could be the reason for that?
3. My 6-month-old baby coughs and vomits quite often. What should I do?
4. I have a 9-month-old baby. She is not gaining weight. She coughs often and does not feed well. What could be wrong with my baby?
5. My 6-year-old daughter snores very loudly during sleep. Sometimes she coughs also. Is it serious?
6. I have a 5-year-old son. He has bouts of cough at night and gets up from sleep. This is happening for the last 6 months. What could be wrong with him?
7. My 6-year-old son is not growing well as compared to his friends of the same age group and has pneumonia four to five times till now. What could be wrong with him?
8. My son is 3-year-old now. He gets fever, cold, and cough very often. What could be wrong with him?
9. My 15-year-old son has developed this cough for last almost 3 months. He coughs very often during the day but has sound sleep at night. I am tired of his cough. How can I help him?
10. My 5-year-old daughter gets cold and coughs very often. What should I give to boost her immunity?