Sore throat, cough, fatigue, sinus pain 2 weeks ago. feeling great now but still have slight cough and some yellow mucus in nose. am i still infected?

Not likely: You most likely have some remnants of the sinus drainage from when you were ill. Stay hydrated and take lots of Vit C and Zinc to help your immune system. Look out for fever and worsening symptoms (cough; sinus pain; etc) as signs of regression of your sinus infection. Good luck

Cough: the cough may indicate a mild viral bronchitis. Hydrate, try some plain mucinex (guaifenesin). For your nose try a saline spray three times a day