There is no harm if a pilgrim engages in trade and business during Hajj or ‘Umrah.
Ibn ‘Abbas said: “In the beginning when Hajj was prescribed, the people used to trade at Mina, ‘Arafah, and the market place of Zhul-Majaz (A place close to ‘Arafah) during the Hajj season, but they feared it might be forbidden for them while in a state of ihram. Thereupon Allah revealed the verse (Qur’an 2.198): “It is no crime in you if you seek of the bounty of your Lord (during pilgrimage).” This is reported by Bukhari, Muslim and Nasa’i.
Commenting on the above verse, Ibn ‘Abbas adds: “The people used to shun business while in Mina, so they were instructed to engage in business or trade while pouring down from ‘Arafah. Abu Omamah At-Taimi narrates that he said to Ibn ‘Umar: “I rent mounts to people during Hajj season, and the people tell me that my Hajj is void.” Ibn ‘Umar asked him: “Do you not don Hajj garb, say talbiyah, go around the House of Allah, pour down from ‘Arafah, and stone the Satan?” The man said, “Yes, I do.” Ibn ‘Umar said: “Then your Hajj is quite valid (and you will be rewarded for it). A person came to the Prophet (peace be upon him) and asked him something similar to what you asked me, whereupon the Prophet (peace be upon him) remained silent until this verse (Qur’an 2.198) was revealed to him: “It is no crime in you if you seek the bounty of your Lord (during Hajj season).” Then the Prophet (peace be upon him) sent for the man and recited the verse to him, saying: “Your Hajj is valid.” This is reported by Abu Daw’ud and Sa’id ibn Mansur. Al-Hafiz Al-Munzhri said Abu Omamah is not known (as a narrator).
Ibn ‘Abbas says that a man asked him: “I hire myself to these people to guide them in performing their rites of Hajj; will I have a reward for Hajj?” Ibn ‘Abbas said: “Yes.” (And then he recited) “To these will be allotted what they have earned; and Allah is quick in account.” (Qur’an 2.202) This is transmitted by Al-Baihaqi and Ad-Daraqutni.