How Long Does Headache Last After Recovering From Flu?

I had what I assume was a virus that lasted about 5 days. Syptoms: body aches, stiff neck, chills, slight nausea, low grade headache but no fever. It's been 9 days since onset and the headache has not completely gone away and seems to get stronger and more painful when I am under a lot of stress. I never suffered from headaches before this virus. Do I need to see a dr about the headache? Also, how long can headaches last after a virus?