External Rotation of Shoulder Pain: Why It Happens & How to Fix It

You reach back to grab the seatbelt, or maybe you're just trying to wash your hair, and suddenly a sharp, arresting ache shoots through the back or side of your shoulder. If this sounds familiar, you are likely dealing with external rotation of shoulder pain.

This isn't just general soreness. It is a specific mechanical issue involving the rotator cuff muscles responsible for turning your arm outward. Ignoring this signal often leads to frozen shoulder or tears that require surgery. The good news? Most cases are mechanical and fixable with the right approach.

Key Takeaways

• The Culprits: Pain usually stems from the Infraspinatus or Teres Minor (posterior rotator cuff) or subacromial impingement.
• The Cause: Often caused by the shoulder being stuck in a forward posture, placing excessive tension on the back of the shoulder.
• Internal vs. External: Pain on internal rotation of shoulder usually suggests subscapularis issues, while external rotation pain points to the posterior cuff.
• The Fix: Treatment requires releasing tight pecs and strengthening the external rotators through isometric and eccentric loading.

The Mechanics: Why Your Shoulder Hurts External Rotation

To fix the issue, you have to understand the machinery. Your shoulder is a ball-and-socket joint, but it’s held in place by the rotator cuff. When you experience pain with external rotation of shoulder, it is almost always an issue with the Infraspinatus or the Teres Minor.

These two small muscles sit on the back of your shoulder blade. Their job is to rotate the arm outward. If you have posterior shoulder pain with external rotation, these muscles are likely strained, tendinopathic, or actively tearing.

The "Stuck" Shoulder Theory

Ironically, pain externally rotating shoulder is often caused by the opposite movement. Many of us spend our days hunched over computers or phones. This leaves the shoulder stuck in internal rotation for hours at a time.

When the shoulder is chronically rolled forward (internally rotated), the muscles on the back of the shoulder are stretched taut, like a rubber band pulled to its limit. When you then force the arm into external rotation, you are yanking on an already overstretched, angry muscle. That is where the snap and pain come from.

Distinguishing the Pain: Internal vs. External

Diagnosing yourself requires comparing movements. You need to know if the shoulder hurts during external rotation or if you are actually feeling pain on internal rotation of shoulder.

External Rotation Pain Indicators

If you feel pain when externally rotating shoulder (turning your arm out), look for:

• Sharp pain deep in the back of the shoulder.
• Weakness when trying to brush your hair.
• Pain when cocking the arm back to throw.

Internal Rotation Pain Indicators

Conversely, shoulder internal rotation pain treatment is different because the injury is different. If you have pain with shoulder internal rotation (reaching behind your back to tuck in a shirt), the issue is likely the Subscapularis (the muscle on the front/underside of the blade) or biceps tendonitis.

If your shoulder hurts internal rotation movements, do not use the external rotation rehab exercises below, as you might aggravate the condition.

Shoulder External Rotation Pain Treatment and Rehab

If you have confirmed that you have pain on external rotation of shoulder, you need a protocol that quiets the angry tissue and restores capacity.

1. Release the Anterior Chain

Because your shoulder is likely stuck forward, you must loosen the chest (Pecs) and Lats. Tight lats are a major cause of shoulder pain during external rotation because they actively fight the movement.

The Move: Use a lacrosse ball against a wall to massage the pec minor (the spot right near the armpit). Spend 2 minutes there before training.

2. Isometric Holds

If moving hurts, don't move. Use isometrics. Stand sideways to a wall. Bend your elbow 90 degrees. Press the back of your wrist into the wall (attempting external rotation) but don't let the arm move. Push gently for 30 seconds.

This activates the rotator cuff without the grinding sensation associated with pain with external rotation.

3. Side-Lying Wiper

Once the acute external rotation pain subsides, lie on your side. Keep the top elbow pinned to your hip. holding a light weight (even a soup can works), rotate the arm toward the ceiling. Control the descent slowly. The slow lowering phase (eccentric) is vital for tendon repair.

My Personal Experience with External Rotation of Shoulder Pain

I didn't just read about this in a textbook; I lost about six months of bench pressing to it. It started as a dull ache, specifically when I would un-rack the barbell—that moment where the arms accept the load and rotate slightly outward.

The most frustrating part wasn't the gym, though. It was sleeping. I remember waking up every time I rolled onto that side, feeling this very specific, burning "knot" right behind my rear delt. It felt like someone was pressing a hot coin against my shoulder blade.

I made the mistake of just stretching it. I thought, "It feels tight, I should stretch it." That was wrong. Stretching the back of the shoulder actually made it worse because, as I mentioned earlier, those muscles were already over-lengthened from my desk posture. The moment I stopped stretching the pain and started doing isometric external rotations (pressing my hand against a doorframe) and smashing my pecs with a lacrosse ball, the relief was almost immediate. The grit felt in the pec minor was nauseating, but releasing that tension finally gave my external rotators some slack.

Conclusion

Dealing with pain with shoulder external rotation requires patience and a shift in strategy. You cannot stretch your way out of this if the issue is weakness or over-lengthening. Focus on releasing the front of the body and strengthening the back. If the shoulder hurts external rotation movements for more than two weeks despite this rehab, see a physical therapist to rule out a labral tear.

Frequently Asked Questions

Why does my shoulder hurt when I rotate it outwards?

This is typically caused by tendonitis or a strain in the Infraspinatus or Teres Minor muscles. It can also be a symptom of shoulder impingement, where the rotator cuff tendons are pinched between the arm bone and the shoulder blade.

What is the best exercise for external rotation pain?

Isometric holds are the safest starting point. Pressing the back of your hand against a wall (without moving the arm) activates the muscle without grinding the joint. Once pain subsides, side-lying external rotations with light weight are effective.

How do I know if I have a rotator cuff tear?

While an MRI is the only definitive test, a significant tear often presents as profound weakness, not just pain. If you cannot hold your arm out to the side or if it drops uncontrollably when you try to lower it slowly, you should seek medical attention immediately.