Ice or Heat
Studies show that using cold or hot therapy to treat pain and muscle cramp is highly effective. If the cramp persists for a long period, you can apply an ice pack on the muscle for about 15-20 minutes at once, several times a day. Ensure you wrap the ice in a thin towel or cloth so that the ice is not placed directly on the skin.
A heating pad [1] in the area may also be effective for 15 to 20 minutes at a time, but follow this with an ice pack. This is because while heat feels good for pain, it may worsen inflammation. Ice will calm down the inflammation.
Other heat options include a warm bath, hot shower, or a hot tub or spa if you have access to one, which can all help relax your muscles.