If Jesus is God, why was He unable to do certain things while on earth?
Jesus was never limited by His inability to perform supernatural feats. On several occasions, the Lord proved that He still had the power to control the material realm. He had the power to walk on water, He knew the thoughts of those who schemed against Him, and He could predict the future.
At no time was Jesus the victim of fate. Throughout His whole life, He was following a detailed plan that was laid out from the beginning of time.
The only thing that limited Jesus on earth was people's lack of faith. And the limitation was really a reaction to people's unwillingness to believe in the working power of God. Jesus could have performed any miracle He wanted in His hometown of Nazareth, but He chose not to because of the residents--disbelief.