Shoulder Injury Exercises Shoulder Injury Possibly While Weight Training- What Exactly Happened To Me?

Shoulder injury possibly while weight training- what exactly happened to me? - shoulder injury exercises

A couple of weeks, I noticed a pain in the left shoulder. If you break my arm, I feel nothing, but if I pull the arm forward to heading to the gallows, or if I my arm as if to touch his back, stretching can be very painful. What type of injury is it? Can be extended too much, or lift heavy weights, makes the shoulder exercises? The strangest thing is that the injury has gradually become clearer in the first two days, and I can not identify the cause.