Good evening, yesterday evening a wooden chair fell on my foot. my foot is a little bruised and swollen on the area. but why is there a constant burning sensation on the bruised area?

Contused nerve: It occurs because of a contusion to a nerve on the top of your foot. It will resolve with time.

Varies: I would consider being seen to make sure there is not an associated fracture. Other possible causes could be that the blunt force injured the nerve that runs in top of the foot, or you may have a hematoma associated with the injury as well. Be seen for an accurate diagnosis.