Just had a neck xray and didn't have breasts shielded . i forgot to ask. is that a concern and should i have had it?

No need to worry: An x-ray typically provides a fraction of the radiation dose one might receive just from background radiation in one year. A ballpark amount is the radiation you might receive on a transcontinental flight. As the breasts are not in the field-of-view, the radiation exposure to them is even less. Any risk of cancer from a neck x-ray is essentially nil.