Lower trapezius pain may be related to the following causes: 1. There may be trauma to this area. The most common case is a sudden violent pull on the upper limb, or a sudden excessive internal rotation of the shoulder joint on this side, which can lead to a pull on the muscles here, which can cause damage and result in pain. In addition, if there is a direct violent blow to the shoulder joint, it will also cause muscle damage and pain. 2. This condition may be caused by cold, such as inadequate clothing or contact with cold objects, which may cause muscle spasm and pain. 3. 4.It may also be caused by poor posture, such as poor sitting posture, or propping up the upper body with one upper limb for a long time while lying down, which may cause muscle spasm and pain.