Why Does My Shoulder Hurt When I Throw?

Pitching With Pain: Why Shoulder Soreness Happens 

You're on the mound, mid-inning, and that familiar ache creeps into your shoulder. Maybe it's a pinch. Maybe it's a lingering dull throb. Either way—it’s holding you back.

As a double board-certified Sports and Orthopaedic PT and fellowship-trained manual therapist, I’ve helped hundreds of baseball athletes understand one thing: shoulder pain doesn’t have to be a career-ender. Here's why your shoulder hurts when you throw—and how to fix it before it gets worse.

Throwing Mechanics Put Your Shoulder to the Test 

Throwing a baseball is one of the most violent movements in sports. At peak velocity, your shoulder can rotate at over 7,000 degrees per second. That force has to go somewhere.

The "thrower’s paradox" explains the dilemma: your shoulder must be incredibly mobile—but also stable enough to handle that intensity without breaking down.

If one link in the kinetic chain is off—like poor core stability, a weak rotator cuff, or limited scapular control—stress shifts to the shoulder. And that’s when pain, and even velocity loss, starts showing up.

Rotator Cuff Strain: The First Red Flag 

Your rotator cuff stabilizes the shoulder during high-speed motion. But the repetitive stress of throwing creates microtrauma—leading to rotator cuff tendinopathy or even tears.

Research shows that in pitchers, these tears often occur underneath the tendon—right where it rubs against the humeral head. That’s why internal loading tests often reveal pain before an MRI ever does.

GIRD: A Silent Threat to the Posterior Shoulder 

Glenohumeral Internal Rotation Deficit (GIRD) is still taught in PT programs because it’s a real contributor to shoulder pain.

If you don’t maintain posterior capsule mobility, tightness sets in. This reduces internal rotation and shifts stress to the labrum. One study found 60% of pitchers with GIRD of 35° or more developed shoulder pain significant enough to miss playing time.

Scapular Dyskinesis: The Chain Breaker 

Your scapula isn’t just a bone—it’s a dynamic foundation. During the throwing motion, it must move in sync with your humerus to allow full cocking and acceleration.

If you have a "SICK scapula" (scapular malposition, inferior medial border prominence, coracoid pain, and dyskinesis), the shoulder loses that smooth coordination. This instability often results in sharp pain, labral overload, or even rotator cuff failure.

Pitching History Holds the Clues 

Diagnosing shoulder pain isn’t just about tests—it’s about timing. When in the throwing motion does pain occur? During which pitch type?

Pain at late cocking usually points to posterior labral stress or biceps anchor involvement. Pain after ball release may hint at rotator cuff overload. These clues shape how we treat it.

Stretching to Restore Internal Rotation 

One of my go-to drills is the sidelying cross-body stretch. It specifically targets posterior capsule tightness, restoring internal rotation.

In fact, studies show that posterior capsule stretching alone can resolve GIRD in over 90% of pitchers. And that’s a game-changer.

Rehab First. Surgery Last. Always. 

If pain has already set in, conservative care is your best friend. That means rest, targeted rehab exercises, and often—adjustments in your mechanics.

Rotator cuff repair surgery has a brutal stat: only 8% of pro pitchers who get it return to their prior level. That’s why prevention and early action are everything.

Train the Full Chain—Not Just the Shoulder 

True shoulder health isn’t about banded external rotation alone. It’s about restoring the full kinetic chain.

That means training leg drive, core control, scapular mechanics, and posterior cuff strength—together. If one area underperforms, the shoulder pays the price.

Keep Shoulder Pain From Ending Your Season 

If your shoulder hurts when you throw, don’t wait.

Address it now—before it becomes a season-ending injury. Build strength, restore mobility, refine your mechanics, and get a proper evaluation.

I specialize in helping baseball athletes overcome shoulder pain and get back to throwing gas. 

Interested in learning more? Check out our other articles on the shoulder, or contact me directly to tailor a program that’s right for you:

1. Shoulder Pain in Baseball: What Every Thrower Must Know
2. Overcoming Shoulder Pain: Andrew's Path to Stronger Throws
3. The Complete Guide To Understanding Athlete's Shoulder