On the left side of my back just below my shoulder blade, when i breath i have discomfort. especially big breaths, normal breathing is fine?

Back pain: In. order to resolve your problem the cause must be determined. Pain on breathing is a symptom, not a diagnosis. While most causes are easily resolved, others can be quite serious. Please see a Physician for a comprehensive evaluation, medical history, medication survey, possible lab tests, possible imaging. Only with these data can you be properly diagnosed and then properly treated.