A trigger point can be understood as an exceptionally tender spot within a muscle that elicits pain when pressure is applied, commonly referred to as a "knot." It's that particular area of the muscle that feels abnormal and extremely painful when massaging tight shoulders. Sometimes, trigger points can cause pain even without direct pressure, contributing significantly to the muscular discomfort experienced by many individuals.
As per the foremost experts in trigger point research and the physician credited with introducing the term "myofascial trigger point," a trigger point is described as a "hypersensitive nodule within a tense band of tissue that can radiate pain."