The first thing to consider when you have symptoms of left shoulder pain is whether it is a localized lesion or injury to the shoulder joint. The first thing to consider is whether it is a localized lesion or injury to the shoulder joint. The most common disease that can cause shoulder pain is frozen shoulder. Patients with frozen shoulder are usually middle-aged or older and have shoulder pain along with limited shoulder joint movement, whether it be side planks, front planks, or back extensions, which can be limited by pain. Most patients with frozen shoulder are suffering from adhesions, and the pain may be worse at night. In most cases, the pain is caused by soft tissue injury around the shoulder joint. Most of the injuries are caused by improper sports posture or excessive weight-bearing exercises on the shoulder joint. Moving the shoulder joint can aggravate the pain, which can be relieved after rest.