Overhead throwing athletes are subjected to many different external forces that can affect the shoulder complex. With every pitch, there is a tremendous force placed on the soft tissue and bony structures. This is especially true at the end of your shoulder range of motion — both as you cock your arm back all the way and as you let the ball go during forward motion.
Add the speed and angle of each throw into the mix and you’ve got a recipe for potential problems. Injuries are often the result of many factors such as muscle imbalances and/or muscle weakness. There can be issues with too much or not enough flexibility. Flexibility of soft tissue structures such as the tendons is called tissue extensibility. Looseness of ligaments and the joint structures is referred to as joint laxity. Either of these conditions (and especially when combined together at the same time) can contribute to sudden shoulder injuries.
In point of fact, most of the time, the injuries aren’t sudden at all. They are quite gradual but the player isn’t aware of changes that will eventually result in a problem. It’s probably time for a review of your situation — including a look at your throwing patterns, joint motion, and muscle strength. Talk to your coach about the best way to handle this. Many teams have their own athletic trainers, exercise physiologists, or physical therapists who can evaluate new problems and advise the athlete accordingly.