The short version
- A bursa cushions the tendon that glides under the bone at your shoulder.
- Overhead work or a stiff shoulder blade often keeps the bursa irritated.
- Pain on the outer shoulder that is worse at night is a common sign.
- Rest alone calms a flare but does not fix what caused it.
- Care calms the area, frees the joints, then rebuilds it with exercise.
What a bursa does.
You have small fluid-filled sacs at the points where tendon glides over bone. They work like a cushion, or a bit of grease, so nothing wears against anything else.
The one that causes most shoulder trouble sits under the bony roof at the top of your shoulder, between that bone and your rotator cuff tendon. Every time you lift your arm, the tendon and the bursa slide through that gap.
If the gap gets tight, or the arm goes through it a few thousand times more than usual, the bursa gets irritated and swells. A swollen bursa takes up more space in a gap that was already tight. That is the loop, and it is why bursitis tends to hang around rather than settle in a few days.
What it feels like.
- Pain on the outside or top of the shoulder, sometimes spreading toward the middle of the upper arm, rarely past the elbow.
- A sharp catch in a specific arc as you raise your arm out to the side, often somewhere between shoulder height and overhead.
- Trouble reaching behind you, into a back seat, or for a seatbelt.
- Worse at night, especially lying on that side. This is the complaint that finally brings people in.
- Achy and stiff after rest, easing a little once you move, then getting worse again with use.
Pain that runs down past the elbow, with pins and needles or weakness, is a different story. That usually points at the neck rather than the bursa, and it needs the neck examined.
What keeps irritating it.
Bursitis almost never happens for no reason. Something is closing the gap or overworking it.
A weekend of painting ceilings, a new job with overhead lifting, or a training program that added pressing too fast will do it. So will a shoulder blade that does not glide properly, which is common in people who sit at a desk with a rounded upper back. If the blade does not rotate as your arm goes up, the roof of the shoulder does not get out of the way, and the bursa pays for it.
A stiff mid-back and a stiff neck feed the same problem. That is why we look at all three rather than only the sore shoulder.
Rest alone rarely fixes bursitis. It settles the flare and leaves the cause in place, so it comes back the next time you paint a ceiling. Resting it means backing off the aggravating movement while you change what closed the gap. Ignoring it means doing nothing and hoping.
What we do about it.
Your first visit is an exam. Dr. Boss moves your arm for you and watches you move it yourself. He tests the positions that load the space under that bony roof, to see which one reproduces your pain. He watches your shoulder blade as your arm goes up. He checks your neck and mid-back, and tests reflexes, grip and sensation if anything travels down the arm. Then he shows you what he found on a 3D model of the spine.
Treatment then has three parts.
Calm it down. Back off the movement that keeps flaring it for a couple of weeks. Ice can help in the first days. Sleep with a pillow under that arm so the shoulder is not hanging forward all night.
Open the gap. We free up the stiff joints in the mid-back and neck, and use massage therapy and soft tissue work on the muscles around the blade and the cuff. When the blade moves again and the upper back is not locked, the arm has more room to travel.
Keep it open. This is the part that decides whether it comes back. Rows, wall slides, shoulder blade squeezes, and light rotator cuff work with a band. Therapeutic exercises give you the ones that match your exam. Ten minutes most days beats an hour on Sunday.
How long.
A flare that is a few weeks old often settles over a course of care across several weeks. A shoulder that has been sore for a year takes longer, because you are rebuilding movement habits as well as calming tissue.
Dr. Boss gives you a real number of visits at the start and checks against it as you go. If the shoulder is not responding the way we expected, or if the exam points to a tear or something that needs imaging, he will tell you and send you on. Shoulder pain treatment here starts with finding out what you actually have.
Reviewed by Dr. Christopher Boss, DC, Boss Chiropractic. Last updated September 11, 2026.
This page is general information, not medical advice. What is right for you depends on your exam. Dr. Boss will tell you straight whether we can help, and where to go if we cannot.