Arm Straight Back Shoulder Stretch
This stretch does a great job of targeting the front shoulder muscles, but it can be too intense if done in the wrong position. Start by standing or sitting and have your arm at your side with your palm pointing back (knuckles forward). Then move your arm back, without shrugging or raising your shoulder, until you feel a stretch in the front of your shoulder.
The stretch works best if you have something to rest your hand, wrist, or forearm on during the stretch. The key is to find a position where your arm and shoulder can relax, but you still feel a decent stretch. A chair, sofa, or other furniture can work well, but you can use anything that feels comfortable and is the right height.
If your shoulders are tight, you may not have to move your arm back much at all and trying to place your arm too high may overstretch your shoulder or cause discomfort. Start slow and gradually move your arm to higher positions as flexibility improves.
When you become comfortable with this stretch, you can move your hips or chest to increase the stretch to target the tightest area(s) of your shoulder.