The way humans go on about their lives these days is against the way the human body is meant to function. For millions of years, humans have been very mobile. We hunted game, picked up heavy objects, built shelters, and ran away from danger. We are meant to move around. In the modern world, sitting down has become our new bane, so much that they are calling it the new smoking. This results in many problems, in which one of them is having rounded shoulders. Not only do rounded shoulders cause muscular imbalance that could lead to pain and injury, they also make you look quite frankly, like a loser. Confident body language is always accompanied with an open chest and pulled back shoulders.
How do you fix rounded shoulders and correct your posture so it can look badass and function properly? that depends on what you have in mind. If you want a quick fix, there are plenty of stretches and exercise that will fix your rounded shoulders in the short term and they all work. However, if you are looking for a long term strategy to fix your rounded shoulders and have an impeccable shoulders, you have to look for the root cause of the problem and work from there.
Most modern day human activities require you to be in a flexed position. This means you are primarily using the muscles in the front part of your body, which causes your chest and front deltoids to be overdeveloped relative to your back muscles, thus causing rounded shoulders. This happens when you sit down or drive your car. So the first step is, sit down less, and be more active. This requires a change in your lifestyle. Look into standing desks as an option to consider. If you begin to sit down less, you will see automatic improvements in your posture and an improvement in your rounded shoulders.
The other part of the puzzle is strengthening your back muscles. People have the tendency to go to the gym and work out more on front muscles like chest and biceps because they look more aesthetic. This further facilitates the problem of rounded shoulders and makes your posture even worse. A long term strategy to fix rounded shoulders and fix your posture would be to focus more of your training time on pulling movements that work out your back muscles like pullups, lat pulldown, and rows, and less on pushing movements that focus on front part of your body like bench press, pec fly machine, and dumbell flies. This will pull your shoulders back and fix your rounded shoulders in the long term and give you a confident posture that is built to last, and get ladies.