Hi welcome to Health care magic forum. From your description it appears that the fracture
was crack fracture, still you have swelling in the chin and you are feeling the pain means it could be psychological, as it is commen in such cases and at this age, of course it also possibility of remnant pain .
I advise you to consult an orthopedic surgeon for pain relief. He may give you medicines covering actual pain and psychological factor. Besides i advise you to practice diversion procedures as yoga
, gardening etc .
Besides i advise you to follow some diet recommendations as avoid using potato , other tubers, tomato, cauliflower , coconut, egg, chicken, fish and other sea foods for some time as these are said increase the pain.
Wishing for a quick recovery from pain, and thanks for calling.