The difference between pain and soreness is based on where you feel it and how it feels.  If a player comes up to me and tells me that they're feeling something in the back of their shoulder and it's kind of just a dull, full feeling that came on about 24 hours after they threw, I'm going to treat that as soreness. If a player is experiencing the general full feeling of muscles and not discomfort in the joints, that is more than likely soreness.

If a player starts feeling discomfort where the arm bends at the elbow or shoulder, I'm going to address that has pain.  Discomfort on the front of the shoulder and right on the inside part of the elbow are two areas where I would start thinking it would be pain.  That could include a sharp feeling, especially as you throw.   Another characteristic of pain is if it's in a very isolated area, such as on the inside of the elbow or in the front of the shoulder.

In contrast, soreness is a feeling of fullness in the muscle, and is often located on the top of the arm or bicep or the back of the shoulder.  A player usually begins to feel soreness around 24 hours after throwing.

For an in-depth discussion of fatigue, soreness, and pain, check out the article, What's the Difference Between Fatigue, Soreness, and Pain in Your Pitcher? by Dr. Phil Plisky.

Nathan Denning, PT, DPT, SCS, CSCS, Nathan is the owner and physical therapist of Integrated Performance in Carmel, IN. He has extensive experience working with professional athletes including his time as a physical therapist and reconditioning specialist for the Minnesota Twins. He has rehabbed and trained hundreds of athletes from all organizations including: MLB, NFL, NHL, NBA, Olympic athletes, PGA, and members from our Special Operations.