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If there has been no bleeding/spotting at all in the last 3 years then chances of pregnancy are not possible.Even after stoppage of menstrual cycle it takes time for the hormonal levels to be normalised so chances of pregnancy are possible.
It is rare to conceive after 3 years.
Regarding the hot flashes they seem to be due to hormonal levels being low.You can consider taking HRT for the symptoms.Kindly visit a Gynaecologist for the required guidance.
Take care!