If you have ever cut a workout short because of a nagging shoulder, you are not alone. Shoulder pain when lifting is one of the most common complaints seen in active people – from gym regulars and CrossFitters to swimmers and weekend cricketers. The tricky part: the shoulder is a complex joint with many overlapping structures, so the same symptom can mean several different things.
This article breaks down the most common causes, how to tell them apart, and when it is time to stop working around it and get properly assessed.
Why the Shoulder Is So Vulnerable
The shoulder has the greatest range of motion of any joint in the body – which also makes it one of the least stable. It relies on the rotator cuff muscles, the bursa, the AC joint, and surrounding soft tissue to stay centred under load. Any imbalance in strength, mobility, or technique shifts stress onto structures that were not designed to handle it.
Common Causes of Shoulder Pain When Lifting
1. Shoulder Impingement
One of the most frequent culprits. Shoulder impingement happens when the tendons of the rotator cuff get compressed between the bones of the shoulder during overhead or pressing movements. The pain typically appears between roughly 60 and 120 degrees of arm elevation – clinicians call this the “painful arc.”
Common triggers: overhead pressing, lateral raises, upright rows, swimming.
2. Rotator Cuff Strain or Tendinopathy
The rotator cuff is made up of four muscles that control and stabilise the shoulder. Repeated heavy loading, poor technique, or a single overloading event can strain or irritate these muscles and tendons. Pain is usually felt with specific movements – reaching overhead, behind the back, or when lowering weight under control.
3. AC Joint Pain
The acromioclavicular (AC) joint sits at the top of the shoulder where the collarbone meets the shoulder blade. It is particularly loaded by horizontal pressing movements – bench press, push-ups, dips – and can become inflamed with overuse. Pain is localised to the top of the shoulder and often worsens when you cross your arm across your chest.
4. Biceps Tendon Irritation
The long head of the biceps tendon runs through the shoulder and can become irritated with repetitive overhead loading or supinated pulling. You will typically feel this as a deep ache at the front of the shoulder, sometimes with tenderness in the bicipital groove.
5. Muscle Imbalances and Poor Technique
Many shoulder problems in trained individuals are not caused by a discrete injury. They develop from years of imbalanced training – too much pressing, not enough pulling; tight pecs and lats, weak lower traps and serratus anterior. The shoulder gradually loses its ability to move well under load, and pain follows.
Warning Signs That Need Prompt Assessment
Not all shoulder pain during training is equal. These patterns suggest a more serious issue:
- Pain that wakes you up at night
- Significant weakness – not muscle fatigue, but genuine inability to control the weight
- A feeling of instability or the shoulder giving way
- Pain that gets progressively worse despite rest
- Numbness, tingling, or pain radiating down the arm
If any of these apply, stop loading the shoulder and get assessed before continuing.
How a Biokineticist Helps
A biokineticist does not just treat where it hurts – they assess why it hurts. During an initial session, your shoulder mechanics, posture, muscle activation patterns, and movement quality are evaluated to identify the actual source of the problem.
From there, a structured programme addresses the mobility restrictions driving abnormal movement, rotator cuff and scapular stabiliser strength, movement retraining for the exercises causing the pain, and a graduated return to full training load. Training through shoulder pain without addressing the underlying issue almost always makes it worse.
What You Can Do Right Now
- Reduce or avoid the specific movements that provoke the pain
- Avoid upright rows and behind-the-neck exercises until assessed
- Keep doing pain-free pulling movements (seated rows, face pulls) to maintain muscle balance
- Ice the area after activity if there is localised heat or swelling
- Book an assessment – the sooner you get clarity, the sooner you can train properly again
Related reading: 5 Signs You’re Overtraining Your Shoulder | Shoulder Impingement: How Biokinetics Can Help
Ready to find out what is actually going on? Book a session at Nexus Physical Rehab.
Related reading: Shoulder Impingement Syndrome | Shoulder Rehab After Rotator Cuff Injury | 5 Signs You’re Overtraining Your Shoulder