Headache, fever and muscle aches and pains are commonly associated with influenza and bacterial infections but they are also associated with common cold viruses. You cannot separate a cold and flu just from the symptoms. In general influenza has a sudden onset and is associated with fever and muscle aches and pains but a severe common cold can also cause these symptoms. Fever is common in children Fever associated with common cold is uncommon in the adult but quite common in infants and children. A blocked and stuffy nose is one of the most bothersome symptoms of common cold.
Nasal congestion is caused by the swelling of large veins lining the nasal passages.
The degree of swelling of the nasal veins is controlled by nerves which release a chemical called norepinephrine or noradrenaline. Topical and oral nasal decongestants mimic the action of norepinephrine. Cough Cough is usually a later symptom of colds and it is caused by inflammation and infection of the larynx, trachea and lower airways. The dry non productive cough is related to inflammation of the upper airway and the productive chesty cough to inflammation of the lower airways. Some useful references 1.