Shoulder Pain from Sleeping On Your Side

Shoulder Pain: Nature and Potential Causes You Should Be Aware Of

The shoulders are responsible for a wide range of motion. Countless daily movements and routines require them to move and stretch.

Now, the shoulder is a joint that has a ball-and-socket construction. There are three main bones: upper arm bone (the humerus), collarbone (the clavicle), and the shoulder blade (the scapula). There’s also a layer of cartilage for the cushioning, minor joints, and the rotator cuff.

The rotator cuff is what gives the shoulders their range of motion. It is made up of tendons, the tissue that connects muscles with the bones. When the tendons in the rotator cuff are swollen or damaged, it becomes hard for us to move or lift our arms.

Now, let’s move on to shoulder pain from side sleeping.

Here’s what you need to know first:

If you experience shoulder pain when sleeping on your side, there could be multiple reasons for that. And the way you sleep may only be the aggravating factor, while the main cause could be an underlying condition.

So, let’s take a look at possible causes of your shoulder pain.

Shoulder Injury

Side sleeper shoulder pain can originate from the tear in your rotator cuff muscles or the cartilage. Shoulder fracture, dislocation, or the separation of joints may also be possible due to an injury. In this case, your shoulder can look swollen, and you may even see some bruising.

Sleeping Position

Research suggests that your sleep posture is important. When you don’t maintain a healthy posture during sleep, you put too much pressure on your muscles and joints, which can lead to hip, back, neck, and shoulder pain.

Some studies also suggest that sleeping on your side can actually cause shoulder pain due to the postural immobility and the prolonged pressure on one’s shoulder.

Now, the most common sleep-related cause of shoulder pain for side sleepers is an unsuitable mattress. Those who sleep in the lateral position require a generous amount of cushioning for the hips and shoulders. As a side sleeper, you need your mattress to gently hug the shoulders, reducing pressure points.

Unfortunately, many sleepers use mattresses that are too firm for them. As a result, the shoulders don’t sink in deep enough and resist the surface of the mattress. This creates tension in the joints and muscles, which can lead to shoulder pain.

Also read: How to choose the Best Mattress For Side Sleepers With Shoulder Pain and 5 mattress recommendations

Frozen Shoulder

This condition causes shoulder inflammation and can lead to pain and limited mobility. It usually develops over time and can be associated with diabetes, shoulder injuries, and other health issues.

Poor Posture

A commonly overlooked factor, poor posture can put uneven pressure and stress on your muscles, bones, and spine, which can lead to shoulder straining and pain.

Poor posture is typically associated with long hours of sitting, keeping your head down for long periods of time (when using your smartphone, for example), and, of course, an unhealthy sleeping position.

Shoulder Pain Prevalence


Interestingly enough, shoulder pain is quite common among youngsters. This may be related to increased computer use (keeping the static posture and doing repetitive moments) and a less active lifestyle (leading to poor posture as well).

Repetitive Work Injuries

You don’t have to be a professional athlete or a construction worker to have shoulder issues. Any repetitive movement that is being done multiple times daily at work can lead to shoulder strain, injuries, and pain. You could be painting your fence all day or cleaning, for example, and that can put too much pressure on your shoulders. Even something as simple as serving coffee all day might cause shoulder pain.


Now, there are many health conditions that can cause shoulder pain. Swollen tendons in the rotator cuff (also known as the tendinitis), arthritis, and shoulder impingement can also make it challenging to sleep on one side. 

Now, while you cannot self-diagnose, it’s important to watch out for more dangerous symptoms like:

  • constant pain that doesn’t disappear for more than a week;
  • swollen shoulder;
  • fever or chills;
  • limited shoulder mobility;
  • excessive night sweats.

If any of these occur, it’s better to consult your doctor right away.

Physical therapy is a common solution to many shoulder issues. A physical therapist will guide you through the special exercises that are meant to improve your shoulder strength and its range of motion.