Shoulder Pain When Running: Causes and Solutions

Shoulder pain isn’t usually the first thing runners talk about. We’re far more used to discussing knees, calves, hips and feet. But shoulder pain is surprisingly common, especially on longer runs or harder efforts. It can creep in as a dull ache, or it can turn into a tight, burning feeling that makes you want to stop and roll your shoulders every few minutes.

The odd bit of tension now and then isn’t a big deal, but if it keeps happening, it becomes frustrating. It breaks your rhythm, disrupts your form and makes running feel harder than it needs to be. The good news is that most shoulder pain has a few simple, fixable causes. Once you understand what’s behind it, it’s a lot easier to stay relaxed and pain free.

Let’s dive into why shoulders (of all things!) hurt when running, what you can do to ease the pain, and how small changes to your posture and habits can make a big difference.

Why Shoulder Pain Happens When You Run

Tension from everyday stress

A lot of shoulder pain isn’t actually caused by running at all. It comes from the way we sit, drive and work. Many of us hold tension through the upper back and neck without realising it. By the time we get to a run, everything is already tight, and the movement just exaggerates it.

If you’ve had a long day at a desk, or if you’ve been hunched over your phone, you’ll often start your run with your shoulders already creeping up towards your ears. Once they settle there, they tend to stay there. This puts pressure through the neck and gets trapped, which is why the pain often spreads across the upper back.

Poor posture while running

Even runners who don’t generally struggle with tension can fall into habits that cause shoulder pain. One of the most common is hunching. When you round your shoulders, every step puts strain through the areas that should stay relaxed.

Other everyday habits creep in too. Many runners curl their hands into tight fists, pull their elbows in too close or lift their shoulders without noticing. Over the course of a run, this constant tension builds into discomfort.

Fatigue & Poor Fuelling

Fatigue makes everything worse. As you tire, your form naturally tries to collapse. Your arms stop moving smoothly, your shoulders start to lift and your upper body begins to tighten. You can have perfect form at the start of a run and still end up with shoulder pain when the miles build up.

During long runs or races, you can also find that small niggles you don’t notice early on become more noticeable later. If your shoulders already tend to tighten under stress, fatigue amplifies it. This tends to happen even more when your glycogen stores run low, so using a proper fuelling strategy will help you maintain form and stave off shoulder pain for longer.

Breathing patterns

Breathing and tension are closely linked. Shallow breathing encourages tightness across the chest, which forces the shoulders forward. When you’re running, especially if you’re pushing the pace, the body sometimes responds by tightening the muscles around the upper back in an attempt to stabilise your breathing.

Most runners don’t feel this happening. They just feel tightness, then discomfort, then a desire to stretch everything out mid-run.

Weak upper body muscles

Running is mainly a lower body sport, but the upper body plays a bigger role than people realise. Your shoulders and arms help balance the movement of your legs. If the muscles supporting your shoulders and upper back are weak, they fatigue quickly. Once they fatigue, the rest of your running form breaks down to compensate, which leads to pain.

This is particularly common in runners who do lots of mileage but no strength work.

A backpack or hydration vest

If you wear a running vest or a small backpack, this can easily cause shoulder pain. Even light packs put pressure through the front of the shoulders. If the straps are too tight or the weight isn’t balanced, the muscles spend the entire run working harder than they should.

This isn’t to say you shouldn’t use a vest. They’re useful and almost essential for long runs and ultras. But small adjustments make a big difference, and many runners never tweak the fit beyond the first attempt.

Old injuries and imbalances

Some shoulder pain has nothing to do with your running form. Old injuries, past weight training habits or general strength imbalances can affect the way you carry yourself. If one side is tighter or weaker, running exposes the imbalance. You end up compensating without realising it, and that compensation shows up as pain.

If you always get shoulder pain on the same side, this is usually the reason.

Signs You Might Be Contributing to the Problem

Sometimes the signs are obvious. Other times you don’t realise how tense you are until someone points it out. These are the habits that often contribute without you noticing:

• Shoulders creeping upwards
  
  

• Hands tightly clenched
  
  

• Arms crossing the body instead of swinging straight
  
  

• Hunching forward when tired
  
  

• Overstriding, which forces the upper body to tense
  
  

• Carrying stress before you even start running
  
  

It can help if you ask a friend to film you running, or run on a treadmill near a mirror. Many people spot issues with their form they otherwise would have missed, and are surprised by how different their form looks from how it feels.

How to Ease Shoulder Pain While Running

Start with a form check

Before you worry about strength or mobility, check the basics. A relaxed upper body makes a huge difference to how your run feels.

Aim for:

• Shoulders relaxed and slightly down
  
  

• Hands loose, with thumbs brushing the top of your pockets
  
  

• Arms swinging comfortably rather than crossing your body
  
  

• A tall posture rather than a hunch
  
  

• A slight forward lean from the ankles instead of the waist
  
  

You don’t need to think about every detail at once. Pick one or two per run. With time, this becomes second nature.

Shake your arms out every so often

A simple reset goes a long way. On long runs, take a couple of seconds to shake out your arms, roll your shoulders and loosen your hands. It stops tension building to the point where it becomes painful.

Breathe more deeply

Shallow breathing encourages tightness. Try to breathe from lower in your ribcage rather than lifting your shoulders with each breath. A steady rhythm helps relax the upper body, especially during harder efforts.

Practice this on easy runs. Once it becomes normal, you’ll find it much easier to keep tension away.

Improve your mobility

If your shoulders or upper back are stiff before you even start running, they’re likely to tighten faster. A few minutes of mobility each day makes a huge difference. Useful exercises include:

• Neck circles
  
  

• Gentle shoulder rolls
  
  

• Upper-back rotations
  
  

• Chest-opening stretches
  
  

Nothing needs to be intense. The goal is simply to keep everything moving freely.

Strengthen the upper back and shoulders

A bit of strength work for runners goes a long way. You don’t need to lift heavy weights. Light, regular strength training helps the muscles that stabilise the shoulders stay strong on longer runs.

Good exercises include:

• Band pull-aparts
  
  

• Face pulls with a resistance band
  
  

• Light rowing movements
  
  

• External rotations for shoulder stability
  
  

Two or three short sessions a week are enough to build strength and improve endurance in the muscles that keep your shoulders in a good position during running.

Adjust your running pack

If you run with a vest, experiment with the straps. Too loose and it bounces; too tight and it digs into the shoulders. You want the weight balanced evenly so the shoulders aren’t pulled forward.

If you carry bottles on the front, make sure both sides are filled evenly. Many runners unknowingly create imbalance by running with only one side loaded.

Warm up properly

A good warm up gets blood flowing to the shoulders and upper back, which helps them stay relaxed once you start moving. Include simple arm swings, gentle twists and a couple of posture checks. It doesn’t need to be long. Two minutes is often enough.

Reduce stress away from running

If your shoulders are always tense, running will highlight it. A few lifestyle tweaks help reduce this general tension:

• Adjust your desk setup
  
  

• Take breaks to stretch during the day
  
  

• Avoid hunching over your phone
  
  

• Try simple breathing exercises
  
  

If you start your run relaxed, you’re far less likely to develop shoulder pain once you get moving.

When Shoulder Pain Signals Something More Serious

Most shoulder pain is caused by tension or form issues. But if you experience any of the following, it might be worth speaking to a physio or GP:

• Pain that gets worse over weeks
  
  

• Pain that spreads down the arm
  
  

• Weakness or numbness
  
  

• Pain that stops you lifting your arm normally
  
  

This doesn’t mean you’ve done anything serious. Often it’s just a tight nerve pathway or a stubborn imbalance. A physio can identify the exact cause and give you specific exercises to fix it.

How Shoulder Relaxation Helps Your Overall Running

Running feels easier when the upper body isn’t fighting the lower body. Once your shoulders stay relaxed, you use less energy, your breathing improves and your posture stays more stable. Many runners are surprised by how much smoother their stride feels.

It also helps during races. When fatigue hits, runners often tighten up without noticing. If you’ve built good habits, it’s much easier to stop that tension building.

And if you use natural fuelling on the run, relaxed shoulders help you take things in more easily.

Shoulder pain when running is annoying, but it’s rarely mysterious. Most of the time it comes from tension, poor posture or everyday habits that carry over into your runs. With a few small fixes, you can keep your shoulders relaxed and enjoy smoother, more comfortable miles.

Start by checking your form, relaxing your hands and keeping your breathing steady. Add a little strength work, improve your mobility and adjust your running pack if you use one. None of these changes need to be complicated. Small steps add up fast!