My 20m girl was coughing throughout the whole of last night. And in btw, I could hear wheezing sounds when she breathed. What could be the reasons for the wheezing sounds? She doesn't has blocked nose not runny nose.

It could be that her airways is blocked. Please check on her to ensure that she is breathing well else you may have to bring her to the nearest GP or A&E. This is not a joking matter and please put it in your 1st priority.