Ii have these white pore like bumps under my breasts and II can squeeze them and white stuff comes out they don't hurt...What is this?

Sebaceous glands. The oil glands of the skin are called sebaceous glands. If they become obstructed the sebum accumulates and you see the whitish bumps - small sebaceous cysts. If they become infected they will be pimples, the larger ones are sometimes called "boils". An exfollient can help to minimize these.