The number-one reason why your shoulders are always killing you

But when you go to grab your microwave popcorn stash from the top shelf of your pantry, you wince. And then, when you try to uncork the bottle of wine, you struggle. You’re sore, and it’s not because you’ve been on your feet handling the nation’s capital’s messiest dramas, love triangles, and secret spy organizations. But you also haven’t done any shoulder-specific workouts lately. So why are your achy shoulders keeping you from living your best Fitz-and-Jake-loving life?

“The shoulder is the most mobile joint in the body, which means there are a lot of things that can go wrong with it,” says Mike Riccardi, a physical therapist at Finish Line Physical Therapy in New York City. “If your shoulders hurt, it’s probably from a combination of a few things, because the shoulder joint is complex. But the one overarching cause is poor posture.” (Did you just straighten up in your chair?)

According to Riccardi, poor posture can cause muscle imbalances with certain muscles getting too tight and others getting too stretched out and weaker. “These imbalances in strength and tension cause the humerus—or the arm bone—to not sit perfectly well on the shoulder blade,” he says. And since those imbalances are often the result of sitting at a desk or hunching over a keyboard all day, fixing your posture is crucial if you want your shoulders to stop hurting and function the way they should. (And so you can reach your popcorn and eat it, too!)

So why exactly is the shoulder joint considered to be so complex? “There’s a lot to it,” says Riccardi. “It’s the articulation of your humerus on your scapula. The arm moves on the shoulder blade, and the shoulder blade moves on the ribcage. There’s also the clavicle, which interacts with the sternum and the scapula. With so much going on, anything from common muscle strains to ligament sprains, rotator cuff tears, labral tears, bursitis, dislocations, subluxations, and ligamentous laxity can all affect the shoulder and cause pain or discomfort.”

If you have perfect posture and your shoulders still hurt, there are a few reasons why. While some of injuries are brought on by overuse or too much exercise with poor form, others—like labral or rotator cuff tears—could be more traumatic in nature. “Although pain in the shoulders might not necessarily be from exercising or a car accident, for example, you can get pain in your shoulders without overuse or trauma,” Riccardi says. “One of the most common injuries affecting the shoulder is what’s called shoulder impingement. That’s when the slide and glide of the two bones don’t match up perfectly, and something ends up getting pinched when you’re doing something like reaching overhead.” If the pain persists, always see a doctor—and consider getting a step stool for those hard-to-reach nighttime snacks.

Riccardi says that step one of fixing your posture should be to open up your chest, so start by lying vertically on a foam roller so it's along the length of your spine, then let your arms hang out to the side, bending at the elbows to a 90-degree angle. This will help open up your pectoral muscles, releasing some pressure in your back. While this is a great starting point, definitely make an appointment with a doctor or physical therapist, who can help you fix the problem for good.