Having the correct body posture and alignment is optimal for keeping your body balanced. The two words are different, but need for your body. Body alignment factors in function. Body posture is static and can be good or bad.
An easy way to improve your body posture is to stand in front of the mirror and align your ears, shoulders, and hips. Posture works with alignment to improve on your posture. Proper alignment places your ears loosely above above your shoulders and above your hips. Your spine is a nature “s” curve so you will find that it does not hurt. You are aligning with the natural “s” curve of your spine.
There are other ways to improve on your posture and alignment. Pull in your core, especially when sitting because it also helps with the natural “s” curve of your spine. It also strengthens your core muscles too. In order to do this, a habit must be broken and that is slouching in your seat. The majority of people do, especially when on the couch. It messes up the alignment of your spine, which causes you to slouch in other chairs. This also happens when you get tired. One way to prevent this is standing up every 15-45 minutes or depending on when you start feeling fatigued.
I was known to have broad shoulders because I am tall. I never developed back problems which is surprising because I always carried a heavy backpack in high school. If my back began hurting, I would always take it off immediately and stretching. Stretching is the best thing you can do for your body, posture, and alignment. Try doing some stretching exercises or yoga first thing in the morning and in the evening. It will definitely help with your body and even brighten up your day.