Why Does My Shoulder Hurt at Night but Feel Okay During the Day?

The Midnight Mystery

You make it through your workday fine. You drive home, cook dinner, maybe even throw a ball for the dog. But the moment you lie down to sleep, your shoulder starts aching. By 2 AM, you're wandering the house, trying to find a position that doesn't hurt.

This pattern frustrates patients more than almost anything else I see in my Durango practice. A horse trainer from Mancos told me last year, "Doc, I can saddle a horse without thinking about it, but I can't sleep more than three hours at a time." It seems backwards—shouldn't rest make things better?

The answer lies in understanding what's actually happening inside your shoulder when you change positions.

What Changes When You Lie Down

During the day, your arm hangs at your side, and gravity gently pulls it downward. This actually creates a small amount of space in your shoulder joint, giving the irritated tendons room to breathe. When you lie down, that gravitational assistance disappears.

Several things happen simultaneously. The structures inside your shoulder compress together. Blood flow patterns change, and inflammatory fluid that accumulated during the day settles into the injured area. If you sleep on the affected side, you're adding direct pressure to already irritated tissue. If you sleep on the opposite side, your arm falls across your body and stretches the damaged structures.

Think of it like a bruise on your shin. Walking around during the day, you barely notice it. But bump it against the coffee table, and suddenly you remember exactly where it is. Your shoulder tendons experience something similar when compressed against bone for hours at night.

Common Culprits Behind Nighttime Shoulder Pain

Several conditions are notorious for causing this day-night disparity.

Rotator cuff problems top the list. Whether you have tendinitis, a partial tear, or a full tear, the rotator cuff tendons sit in a tight space between bones. Lying down narrows that space further. I'd estimate that eight out of ten patients I see for nighttime shoulder pain have some degree of rotator cuff involvement.

Shoulder bursitis creates a similar pattern. The bursa is a fluid-filled cushion that helps tendons glide smoothly. When it becomes inflamed and swollen, the added bulk has nowhere to go when you lie down—it gets squeezed between bone and tendon.

Frozen shoulder, or adhesive capsulitis, often announces itself at night first. The shoulder capsule tightens and becomes inflamed, and the still positions of sleep seem to aggravate it more than daytime movement.

Arthritis can also produce nighttime symptoms, especially as inflammation accumulates when you're not moving the joint.

Why Your Body Isn't Warning You During the Day

Your shoulder is actually sounding the alarm all day—you're just too busy to hear it. Activity increases blood flow and keeps inflammatory fluid from pooling. Movement also triggers your body's natural pain-modulating systems. Your brain is occupied with tasks, conversations, and decisions, so it filters out low-level discomfort.

At night, those distractions disappear. You're lying still in a dark room with nothing to focus on except the signals your body is sending. The discomfort that registered as background noise during the day suddenly becomes impossible to ignore.

A retired firefighter from Bayfield described it perfectly: "During the day, I'm busy enough that I can pretend nothing's wrong. At night, there's no hiding from it."

What You Can Do Tonight

While you're figuring out the underlying cause, a few strategies can help you sleep better. These revolve around finding a comfortable position for the shoulder, and trying to decrease inflammation before bed.

Pillow positioning makes a significant difference. If you sleep on your back, place a small pillow or folded towel under your affected arm to keep it slightly elevated. If you sleep on your unaffected side, hug a pillow to prevent your sore arm from falling across your body. Avoid sleeping on the painful shoulder entirely if possible.

Anti-inflammatory medication taken an hour before bed can reduce the overnight swelling that contributes to pain. Over-the-counter options like ibuprofen work for many people, though you should check with your doctor if you take other medications or have stomach or kidney issues.

Ice for fifteen minutes before bed can calm inflammation before you lie down. Some patients prefer heat—there's no universal rule, so use whichever feels better to you.

When to Get It Checked Out

Occasional nighttime shoulder discomfort after heavy activity isn't necessarily alarming. But if you've been losing sleep for more than a few weeks, something is wrong that deserves evaluation.

I recommend scheduling an appointment if your pain wakes you up at all at night, if you can't find any comfortable sleeping position, if you're noticing daytime symptoms starting to creep in, or if you're relying on pain medication every night just to sleep. Also, if you are noticing that you are unable to do activities that you love because of your shoulder pain.

A teacher from Ignacio waited nearly six months before coming to see me. She kept hoping better pillows or a new mattress would solve the problem. By the time we talked, she was exhausted and her rotator cuff tear had grown larger. She told me she wished she'd come in sooner, and I hear that sentiment often.

Finding the Source

Diagnosing the cause of nighttime shoulder pain usually involves a physical examination and often imaging studies. X-rays can reveal arthritis or bone spurs that narrow the space where tendons travel. Frequently, X-ray changes can occur with a chronic rotator cuff tear. An MRI shows soft tissue detail—rotator cuff tears, bursitis, and inflammation all become visible.

Once we identify what's causing your pain, treatment options range from physical therapy and injections to surgical repair, depending on the diagnosis. But the first step is simply understanding why your nights have become so miserable.

Getting Your Sleep Back

The good news is that nighttime shoulder pain almost always has an identifiable cause and a treatment path. You don't have to keep pacing your house at 3 AM, and you don't have to accept exhaustion as your new normal.

A mechanic from Cortez came to my office after two months of terrible sleep. He said the fatigue was affecting his work more than the shoulder itself. After we addressed his rotator cuff bursitis with a cortisone injection and some physical therapy modifications, he was sleeping through the night within three weeks. Not every case resolves that quickly, but most people do find relief once they understand and treat the underlying problem.

Your shoulder is trying to tell you something. The fact that it speaks loudest at night is actually useful information—it points toward certain conditions and away from others.

Let's figure out what it's saying.

You can email Doctor Butzen at doctorbutzen@gmail.com if you have questions. He may request an office visit for complex concerns that require face-to-face discussion.