Hello, More information is needed for a complete answer. I ll try to guess what s missing and give you the best answer that I can. You mentioned having flu but you did not say anything about laboratory investigation. Was there a positive flu test? Did you have an X-ray? Is the pain one-sided? Is it worse when coughing or taking deep breaths? Do you have shortness of breath? What about fever? I would be more worried if you had ongoing fever (even low-grade), one-sided pain, getting worse when breathing particularly if you also felt you can t get enough oxygen. Sometimes inflammation may spread to the outer layer of the lung and cause pleuritis. The same can happen to the heart s lining layer (pericarditis). Besides the above, other serious complications may cause worsening rib pain. You definitely need a gp visit. If the aforementioned symptoms describe your case then you should see your gp right away. I hope you get well! Kind Regards!