Muscle knots in the Gluteus Maximus are usually located in the thickest part of the buttock, especially near the sacrum and top of the pelvis. These muscle knots are a common cause of buttock pain, which can be a deep, aching discomfort. This pain is often localized to the buttock but can also refer pain to the sacrum, lower back, and the back of the thigh. The pain can feel like a nagging ache and is often worsened by activities such as prolonged sitting, climbing stairs, or standing up from a chair.