No. Christians may not fight physically. It's devilish when people hit, beat, or rob us. But many have suffered for righteousness. 

Remember the great Apostle Paul’s hardships. 2 Corinthians11:24-27, “Five different times the Jewish leaders gave me thirty-nine lashesThree times I was beaten with rods. Once I was stoned…I have faced danger from rivers and from robbers…I have faced danger in the cities, in the deserts, and on the seas. And I have faced danger from men who claim to be believers but are not…I have been hungry and thirsty and have often gone without food. I have shivered in the cold…” But Paul never physically fought back. He tried to escape and to protect himself but never used physical force against his enemies. 

Jesus told His followers that they would be persecuted. He said,
Matthew 10:16-19, 21-23, 30-32, “Look, I am sending you out as sheep among wolves. So be as shrewd as snakes and harmless as doves.  But beware! For you will be handed over to the courts and will be flogged with whips in the synagogues. You will stand trial…A brother will betray his brother to death, a father will betray his own child, and children will rebel against their parents and cause them to be killed. And all nations will hate you because you are my followers. But everyone who endures to the end will be saved. When you are persecuted in one town, flee to the next. …And the very hairs on your head are all numbered. So don't be afraid; you are more valuable to God than a whole flock of sparrows. Everyone who acknowledges me publicly here on earth, I will also acknowledge before my Father in heaven.”

God knows about all the evil things that happen to us. He cares so much about us that He even knows how many hairs are in our head. God is always in control. He permits these horrible trials to help us develop our faith and our characters. Just as Jesus learned obedience by suffering, so do we. (See Hebrews 5:8.) We are always to have faith and to behave in a Christ-like manner.

Jesus instructed us how to respond: Matthew 5:39-42, 12, “But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek alsolove your enemies and pray for those who persecute you, that you may be children of your Father in heaven… Rejoice and be glad, because great is your reward in heaven…”

Sadly, the scriptures prophesy that violence will increase in the last days. 2 Timothy 3:1, “There will be terrible times in the last days.” 

We will pray for you. May God strengthen your heart, give you wisdom, and keep you under His wings of love.