Muscle knots are tight, small areas of muscle that feel like lumps or bumps. They form when muscles become tense or are overused. These knots can cause discomfort, pain, or stiffness in the affected area. Full definition
Also, remember to regularly give your shoulders a good stretch, since this can help loosen up the muscles, improve blood circulation and prevent painful muscle knots. (fitnessandpower.com)
Similarly, for release of muscle knots and tension, different body areas can rest on the ball using the body weight to stimulate release in the muscles. (verywellfit.com)
What I didn't know was that most of the pain was caused by muscle knots and all I had to do was to release the tension in these spots. (ashotofadrenaline.net)