Sins are that which are committed by the hands, the feet, the heart, and even the whole body. (Romans 8:13 - For if you live according to the flesh, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.)
But there is something within us that compels us to sin, to commit evil, and this something is sin. (Romans 7:23 - But I see another law at work in me, waging war against the law of my mind and making me a prisoner of the law of sin at work within me.)
An obvious difference between sin and sins is that: sin is singular, and sins are plural. However, we need to distinguish sin and sins. If you cannot see the difference between the two, it will be impossible for you to be clear about your salvation.