Hajj is not obligatory for a person who does ‘Umrah during the months of Hajj
Question

                Before the begining of the month of Haj, I did my umrah before the month of Haj, some one told me that Haj is wajeeb on me now , although I have already did haj 2 years back, please clarify the same?.
Praise be to Allah.
    What this person told you is not correct, because Hajj is 
    only obligatory once in a lifetime, because of the hadeeth of Ibn ‘Abbaas, 
    which says that al-Aqra’ ibn Haabis asked the Prophet  (peace and 
    blessings of Allaah be upon him): “O Messenger of Allaah, is Hajj (to be 
    done) every year or only once?” He said: “One once, and whoever does more 
    than that, it is a voluntary (act of worship).” Narrated by Abu Dawood, 
    1721; classed as saheeh by al-Albaani. 

    Since you did Hajj before that, then you do not have to do 
    Hajj again. 

    There are three months of Hajj: Shawwaal, Dhu’l-Qi’dah and 
    Dhu’l-Hijjah. Perhaps this person understood from the fact that they are 
    called the months of Hajj that whoever does ‘Umrah during these months is 
    obliged to do Hajj. But this is incorrect, rather the reason why they are 
    called the months of Hajj is that Hajj must happen during these months, not 
    before or after them. 

    Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) was 
    asked about a man who did Hajj tamattu’, then after doing ‘Umrah he went 
    back to his city and did not do Hajj – does he have to do anything (offer 
    any expiation or ransom)? 

    He replied: You do not have to do anything, because if a 
    person is doing Hajj tamattu’ and enters ihraam for ‘umrah, then decides not 
    to do Hajj before he enters ihraam for Hajj, then he does not have to offer 
    any expiation or ransom, unless he vowed to do Hajj this year. If he made 
    such a vow then he is obliged to fulfil his vow. 

    Fataawa Ibn ‘Uthaymeen, 2/679.