What Should Be Done About Painful Breast Lumps Near The Armpit That Began During Pregnancy And Are Now Causing Shoulder Pain?

Hello Doctors My wife age 32 have some lumps in right breast upper part (near to armpit),she is a breast feeding mother of 2year baby..it began during pregnancy first trimester, earlier it was painless but slowly it s becoming painful..now it s painful and shoulders are also covered in pain, ultrasound showed lumps but Doctors said not to worry,what can be done now?