My wife has tremendous right side breast pain last 2 days. what is the probable reason and what should do?

Mastitis: Inflammation of the breast tissue can be very painful. Several causes such as infection, engorgement with fluids (such as when pregnant), bruising from trauma, etc. Are a few. It is best she seek medical attention to have the breast assessed and treated for the proper cause, as if there is an infection, she may need an antibiotic, etc. Best wishes.

Some possibilities:: Take your wife to your doctor. Severe and acute breast pain may be mastitis: a breast infection. But there are other possibilities including gall bladder disease (seriously), heart disease, a blood clot in the lung - none of which you want to take lightly. I am concerned by your description of the pain as 'tremendous.' get her seen! good luck. Lgromkomd.

Have her: Evaluated asap for mastitis if there hasn't been any injury directly to breast. Difficult to answer accurately with little information.