Why do we refer Christ as Lord as well as the Son of God?

The Father, The son and The Holy Spirit commonly make the trinity. It is the three forms of a one almighty lord; at the same time, all these three forms have a personality of their own. Therefore according to the doctrine of Trinity, Jesus (The Son) is the same as Father and Spirit; Father is the same as Son and Spirit and vice versa. Jesus Christ is the Son of God because, he entered the Human world by the Holy unification of the Blessed Virgin Mary and the Holy Spirit. Jesus was given the task to represent the Father and The Spirit to the Human Beings.