If i've already had should reconstruction can i have a 2nd operation if my pain continues?

Yes: The term "shoulder reconstruction" can include surgery for fracture or instability, or shoulder replacement. The best chance for a successful 2nd operation is if it is apparent why you still have pain. If the previous procedure appears well done without anything that can be significantly improved on, simply re-doing it may not have a higher rate of success than what was already been done.

Sure: If the 1st surgery was unsuccessful a 2nd can be done if indicated. You should see a shoulder specialist, who does > 250 shoulder cases a year.