Hi thanks for your question.
You had injured your shin while playing soccer.
There were bruising over the injured place and now you’re having swelling over the site.
There could be a small hematoma
(collection of blood under skin) which has not resolved till date or there was a green stick fracture
which has healed producing small swelling.
The best way to differentiate between the 2 is go for X-Ray of your Tibia
consult some physician who will examine the X-Ray to rule out any previous fracture.
Hope I answered your question.