Bad pain in upper left shoulder, numbness of left arm, with some mild upper chest pain? a shoulder injury?

Depends: How did it start?, when did it start?, what were you doing?, what is the distribution of the numbness? Question too ambiguous to give a reasonable opinion.

Dont ignore: These symptoms could represent a shoulder or other musculoskeletal injury, but could also be of cardiac origin. You should be evaluated by your pcp and possible have an ekg or even a stress test done. If you develop sudden crushing chest pain call 911.