How can my mother pay zakat on gold for previous years, and is it permissible for me to take a share of this zakat to be able to get married? Is it permissible to use zakat money to build a small house and get married? Is it permissible to take zakat from more than one source?

It is permissible for a mother to give her zakat money to her son for marriage if he is poor. It is also permissible for a poor person to take zakat to build a dwelling he needs, even if he possesses enough for his daily sustenance and clothing. As for seeking zakat, there is no harm in it for the needy, though it is better to refrain from asking. One can approach charitable organizations or official bodies concerned with matters of charity.