A muscle knot is a painful or tender spot in a muscle. It feels tight and sore, and it often happens in the upper back or legs. They’re not usually harmful, but they can certainly be uncomfortable. In rare cases, muscle knots are a sign of a long-term (or chronic) pain condition.
Chances are, you’ve experienced the tender, achy feeling of a muscle knot at some point in your life. Research has shown that muscle knots may affect up to 85 percent of the population. Muscle knots impair mobility, cause pain, and can reduce a person’s quality of life.