we have had a flu for about a week now and have been coughing. Yesterday started getting sharp pains under breast bones on left side of ches
This could be related to bronchitis that often follows a viral infection like the flu. It may be bacterial in nature and you should see a doctor and get the appropriate treatment. While it may go away on its own, there is always the risk of more serious complications.
Tracheitis (central chest pain) and pneumonia (pain on the sides of the chest) may also be a possibility.
Refer to this article on Bronchitis :