If you have a persistent cough after having the flu, there are a few things you can do. To help with throat pain, you can try taking acetaminophen. Throat lozenges like Halls or Fisherman's Friend can also provide relief. Keeping your nasal passages clean with a saline solution can help reduce sinus pressure and prevent mucus from dripping into your throat, which often causes coughing. Make sure to stay hydrated by drinking plenty of fluids. If your symptoms don't improve after 7 days, it's a good idea to see a doctor. I hope this information helps, and feel free to ask if you have any more questions!