Good shoulder exercises you can do using your body weight.
With a soup can or other light object in each hand, hold our arms out to your sides with your elbow bent 90 degrees so your upper arms are just an inch or two below your shoulders and almost parallel to the floor, and your forearms are pointed in toward your torso.
Keep your upper arms still and use your elbows to rotate your forearms up until they are as close to perpendicular to the floor as possible. Return to the starting position.
Fill your gym bag or carry-on suitcase with books or something else heavy enough to create a challenging weight. Hold the bag by its straps with both hands. Let your arms hang straight down, with your hands 12 to 24 inches apart. (the farther you place them apart, the easier and more natural the exercises is for your shoulders.)
Lift the bag straight up along your torso until your upper arms are parallel to the floor. Pause to feel the contraction in your delts and traps, then slowly return to the starting position, staying in control.
Grab a pair of water bottles and stand with your feet shoulder-width apart, your knees slightly bent, and your arms at your sides.
Maintaining slight bends in your elbows, lift your arms up and out to the sides until they’re parallel to the floor. Pause, then slowly return to the starting position.
Get into the standard pushup position with your hands about shoulder-width apart. Walk your feet forward until they’re 2 ½ to 3 feet behind your hands and your hips stick way up.
Keep your legs straight as you execute a pushup, feeling the work in your shoulders and triceps.