Breast pain in post menopausal women can be present as a normal experience, that, usually subsides after one or two years.
Discomfort in both breast, can be triggered by hormonal replacement therapy.
However, this discomfort should be evaluated by physician to see if more serious underlying condition is present.
It is well know that the risk for breast cancer raises with years.
Not detecting lump does not exclude this possibility.

Best wishes!