Most running injuries respond well to the “RICE” treatment: Rest, Ice, Compression, and Elevation. Ice the trouble spot for ten minutes on, then ten minutes off, repeating as necessary. You should ice as soon as possible after you have been injured, and immediately after a run if you are running with an injury. Combined with compression (with a cold pack, for example) and elevation, icing goes far to reduce pain and swelling. Heat should only be applied to an injury after the inflammation is gone, probably after about 72 hours. If your swelling has gone down quite a bit, but there’s still a little bit of inflammation, try alternating heat and ice after a few days of ice-only treatment.