Hi, I broke my collar bone Dec. 2, 2005. I just started weightlifting again on Friday and it did not hurt much until Saturday and today (Sunday) I cannot throw a football or lift up my arms without a rather sharp pain. Its nothing horrible, but i really cant do anything physical in this state.
The bone may not have healed well (or completely) the first time, and weight lifting may have caused a small fracture to recur. You should definitely go back to the doctor and get it checked out.