The notion that pain in the left shoulder blade needs to be a warning for cancer is false.
Cancer primary or metastatic lesions in the left shoulder blade region do tend to cause painful symptoms, but pain in this region does not mean that cancer is present.
More often than not, non-cancerous conditions are considered when pain is present in this area. For example, myofasciitis of the back of the shoulder, trauma to the back of the shoulder, strain injury to the tissues around the scapula, coronary heart disease and so on.
In the clinical presentation of left scapula pain, we need to first ask whether there is a history of trauma, history of heart disease, and then do CT or MR (magnetic resonance imaging) of the scapula, routine electrocardiogram, and so on.