Kath, ordinarily I'd say this is probably hormonal - but since you've already had a hysterectomy, that's probably not the cause. Pain is occasionally, but seldom a sign of breast cancer; and when it's happening pretty much all over and in both breasts, this points to either something simple and practical (are you getting enough support from your bra?) or something more systemic.

Breast cancer hardly ever presents symptoms in both sides at once; and then, it's almost never pain. I'd suggest you see your doctor about this; and if (s)he can't help, ask for a referral to a breast specialist. It's worth getting to the bottom of, if only for your own comfort. Take care - PJH