I'm not sure what you need help with--help relieving your symptoms, or a diagnosis as to what's causing your problems. If this pain continues and/or worsens, I'd see a doctor as soon as you possibly can, just in case. My guess would be the flu, like you suggested. I know there is something doctors can give you for the flu after you already contracted the virus. It's supposed to shorten the duration of it, and that's a GREAT thing! Good Luck,
Shinty
Have your gall bladder checked out.