Bursa is a small, fluid-filled sac that acts as a cushion for muscles and tendons. Just like those muscles and tendons, the Bursa sac can get pinched and squeezed and become inflamed and cause pain and discomfort in the front of the shoulder.
The level of pain will dictate when throwing program should begin.
Treatment can often start immediately after feeling pain or discomfort. If the pain is low-to-mid intensity, some basic stretches or light strengthening exercises will relieve the pain immediately. Other times it may take a few days. In most cases taking a couple days off throwing will let everything calm down enough to begin a strength, flexibility and short range, low intensity throwing program. THERE IS HEALING POWER IN THROWING!!
There should usually be a level of throwing that can be done without pain, to speed up the recovery process and maintain consistency with the throwing motion.