Is the reward for working in a company that imports both lawful (halal) and unlawful (haram) goods, with the obligation to store the unlawful ones, and there being no other job available, unlawful (haram), or would I incur sin for that?

It is not permissible to store prohibited goods such as alcohol and pork, due to the assistance it provides in sin, as Allah Almighty says: "And do not cooperate in sin and aggression," and as the Prophet, peace and blessings be upon him, said: "Allah has cursed alcohol, its drinker, its server, its seller, its buyer, its presser, the one for whom it is pressed, its carrier, and the one to whom it is carried." The wages from prohibited work are not permissible. However, if a Muslim is compelled to undertake this work and cannot find any other means to meet their basic expenses, then there is no blame upon them for continuing in it until they find permissible work. They may also adopt the view of those who permit such work out of necessity.