I experience pain in my left shoulder during wide grip lat pull-down (more when arms are in the lower part of the movement). I do wide grip pull-ups without any problems at the same time. It also hurts on pecs machine at the open position. Is it flexibility problem? Has it something to do with shoulder exercises on the previous workout?
Several years ago I began feeling a sharp pain in my left shoulder (behind my deltoid muscle, near the joint) during chest exercises.
At first the pain was minor so I kept with my normal weightlifting routine. Over the next few weeks, however, the pain became progressively worse. It finally reached a point where I could no longer do any chest exercises (or some back exercises) without experiencing severe pain in my shoulder.
(Ironically, shoulder exercises including heavy barbell presses were unaffected. I could also continue doing arm exercises, but only slowly and when very still.)
So I rested. I came back a week later. The pain was still there.
I rested longer. I came back two weeks later. The pain was still there.
I was languishing for weeks. Worse, I had no clue about a cause or a remedy.
NOTE: If my scenario above is similar to your current circumstance then read on. Otherwise, my answer below may not apply to you.
Eventually a bodybuilder acquaintance at the gym explained to me that I most likely had an irritated tendon. He showed me a simple exercise to strengthen the shoulder tendon.
In preparing my answer to your question I discovered that the proper term for this condition is:
Rotator Cuff (or Shoulder) Tendonitis
I did the exercise and was quickly back to normal.
Today, whenever I feel a sharp pain coming to life in either of my shoulders, I just do this exercise and I'm right back on track.
The exercise is a standing, external rotation of the rotator cuff with resistance.
Basically, you stand with your elbow fixed to your side. You cross your forearm across your belly to grab a cable pulley which has been set a the same level as your elbow and with proper weight for 10-15 reps (my preference). From that starting position, rotate your forearm out all the way, keeping your elbow in place, like you're creating a semi-circle.
You can also use an elastic band to do this exercise (just make sure to fix it securely).
I wanted to post images here that would clearly illustrate my description, but all images I found online were subject to copyright protection.
However, you can easily find plenty of articles, images and videos describing this exercise. Just google: "external shoulder rotation exercise" (articles), "rotator cuff external rotation" (images) and "rotator cuff exercises" (videos).
I hope this helps. Good luck!