I felt a sharp pain in the middle of a 205lb military press. I'm not sure if I tore mine or just strained it but I was put out of commission for a week and avoided any overhead stuff for a month.
This is a very common problem for weight lifters. They gain muscle strength in their arms and shoulders, but never work their rotator cuffs directly. This often results in injury from either a sudden "snap" during a heavy lift, or a chronic, degenerative pain from years of unbalanced muscle development.
I recommend working in just 2-3 sets of 10 of specific rotator cuff exercises on your shoulder day. There are several variations. Baseball teams usually do a lot of them.
I usually take a light dumbell(5-20lbs), hold it across my chsst while standing, so the dumbell is in front of the opposite shoulder, palm facing down, elbow at 90 degrees. Kind of like the beginning of a "Nazi salute". Then, I rotate at the shoulder so my forearm is pointing up. And lower slowly. This is just one example. Using cables works well too.
-Good luck