Is Edema Causing Swollen Ankle?

hi,i am a 24 years old girl.I am now suffering for ankle swollen.it came at one night when i was cooking ,standing for a long time.it swelled around my ankle and feet.also i noticed pitting edema only under the bone of the ankle.after one day it reduced but not totally.now it starts paining.i checked my blood,kidney,heart,thriod ...everything is ok.i feel achy in my eyes and leg but no red spots.how long it takes to cure from edema due to hit or salt or standing a lon period?