When to use heat or ice on injuries. "Ice is usually recommended to use on an area that has inflammation, which causes it to be red, warm, swollen, and/or painful. Ice is usually used as part of the initial treatment for sprains and strains, and other injuries. Heat is generally recommended for chronic aches and pains, or new and minor muscular pains. People often choose a heat pack for problems like a stiff neck or a sore back. The heat can help improve circulation and reduce muscle spasm.
