Thanks for posting your query
You had an injury
over your shin after a kick over it.
After that swelling and tenderness present at the site of impact.
So it might be a soft tissue
swelling or a minute fracture
After 3 weeks later there is still some swelling & tenderness present, so it might be a fracture in healing stage.
So an x-ray is needed to rule out the fracture.
So you have to visit an orthopaedic surgeon
for exam. & treatment plan acc. to that.