There is only one way to treat a calcaneal stress fracture and that is to get off it. You have to rest, you have to stop running or stop what ever activity you were doing that caused the stress fracture. If its really painful, you may even need to go into an immobilization boot. Find some other activities in the mean time to help maintain your fitness, but avoid weightbearing.
Thats the easy bit. Once the pain has settled which can take a few or more weeks, the hard bit starts. You need to start back with your running or weightbearing activity and be guided by any symptoms. This needs to be a very slow increase and if you don’t take it easy, there is a very high chance that it is going to happen all over again. You need to plan for at least 2-3 months before getting back to full activity levels. Loads need to be slowly and gradually increased over that 2-3 months. There should be no short cuts here.