If you feel your sloutching stand up straight and pay attention to your posture
If you work out, try maybe your training front deltoids to much and leaving rears which would give rounded shoulder look.
So as klinger said "balance you program"
When standing relaxed, do you palms face inward or backward? Rounded shoulders can be caused by a couple differnet things, and the correction will depend on what the cause is. If your palms face inward, most likely you just need to implement a pec / lat stretching routine. If they face backwards, it's likely that your rear shoulder muscles are weak and over stretched from long term postural problems.
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