There are several reasons for shoulder pain: 1. If the shoulder gets windy or cold, there will be obvious symptoms of soreness in the soft tissue of the shoulder. 2. If the shoulder is overworked. When one side of the shoulder is overworked, there will be acute injury to the surrounding muscles and soft tissues, and then there will be soreness and weakness of the shoulder. 3. Is it myofasciitis of the back of the shoulder? When myofasciitis occurs in the back of the shoulder, there will be soreness and pain on one side of the shoulder, accompanied by numbness and weakness in one upper limb, often with a fixed pressure point or a painful trigger point. The pain is more pronounced at night and is common in patients who have been straining for a long time or who have been exposed to wind or cold.