The radiologist said that the breast cyst I have is nothing bad or to worry about, that is just fluid or milk, is still the same size don't hurt, its ok?

Yes, its ok. As long as the radiologist believes the lesion is fluid filled, there is a low likelihood of breast cancer. Also if the lesion has remained stable after several ultrasounds, it is even more encouraging. We usually only aspirate (remove the fluid) if the fluid filled lesion is palpable and/or causing discomfort or if the fluid filled lesion has evidence of debris or solid tissue inside.
Worry never helped. If the ultrasound finds a cyst, then this not something to be concerned about unless it becomes painful or keeps getting larger.