Stiff and sore is a common condition that can be caused by a variety of factors, such as physical activity, poor posture, or even stress. The term 'stiff and sore' can be described by the four-letter word 'ACHY', which is defined as having a dull, aching pain. This type of pain is often associated with muscle tension and can be relieved through stretching, massage, or other forms of physical therapy.