<s>[INST] I am experiencing a sharp pain between my left breast and collar bone, it is worsened by deep heaths sometimes, moving sometimes and even when I stay still the pain becomes sharper, it shoots up towards my shoulder or stays between breast and collar bone. What could this be? Should I see a doctor? [/INST] Hi I did review your concern.Such a sharp pain that worsens with deep breath can be due to musculoskeletal cause or pleurisy or pericardial cause.I would advice you to go see a doctor and get your self examined. At the basic he will do an ECG and get a chest xray done to find out more about the pain.I hope this helps.Wish you all the best.Thank you for choosing healthcare magic. </s>