We always tell people to alternate every twenty minutes with ice and heat for soft tissue injuries that aren't acute; as in just happened. Ice will reduce swelling and inflammation, heat increases blood flow to an area and can help carry away fluids that cause swelling and pain. Heat is never recommended in the immediate period following injury, usually at least 24-48hrs afterward.
Speaking of pain...The mental kind. I just ran about 140 laps on the indoor running track. That's 17.5 miles! I did it in 3 hours and 20 minutes, pretty good for me. So glad that's done, if this weather doesn't improve, I may be doing 20 miles there again next week. I am just so glad the indoor track is an option because its really cold out right now, well below minus twenty with the wind chill