Although Jesus came to earth and had a flesh human body He was not like other men. Jesus did not have a human father. Joseph was not His father. Therefore Jesus did not sin like normal men. But He did experience all the pain that normal men experience.
So when we say that Jesus was fully man what we are saying is that He was born into a human body and experienced life like a human. There where some who thought that Jesus was not a human but like a ghost or that when He died He did not come back to life in his body but came back as a ghost. This is deception, we affirm that Jesus did come in a body was risen from the dead in a body and went into heaven in a body. He will return in a body also.
All Praise the Ancient of Days