Muscle cramps happen when a muscle involuntarily contracts on its own. Usually, you feel a hard lump at the point of pain — that’s the contracted muscle. Cramps usually occur for a reason. If you haven’t strained a muscle, you’re probably cramping because your muscle is fatigued or overused or your body is dehydrated.
Or maybe you’re not getting enough electrolytes, such as potassium or magnesium. These minerals help your muscles work more smoothly, and fluids help your body process the minerals.