Toddler can't stop coughing and sneezing at the same time since she has layer down to sleep two nights in a row why ?

Cold: The most common cause of a short (few days) episode of coughing and sneezing in a toddler is a common cold, which can be caused by a variety of viruses, and typically is not serious. If the symptoms are prolonged or repetitive, environmental allergies are another possibility. If this is a cold, no treatment is necessary other than rest and fluids. "cold medicines" do not help in children.