Hi,Thanks for query.
Calcaneus is a short and stout bone so hairline fracture
may not cause any problem for height or non healing.
Yes you may get the pain at the side in the future but not always.
if untreated fracture may heal without leaving any deformity
Only rest will heal your fracture.
In hairline fracture of calcanium there is no malunion
I think you might got answer of your long question.
Ok and bye.