breast feeding with breast pain

iam really going crazy!!!!!!!!!!!!!! iam 24 years old and just had ababy 3 months ago. iam breast feeding my baby, since i was really young i started having this slight pain in my left breast with left breast slightly larger than the right one. and over the years it started to get stronger but in very distance periods. around my second trimester i started to feel the pain more sharper and experianced lymph nodes pain under armpit,under breast and at the sides of it.then around the 3rd trimester it came back much stronger and including pain at the neck,back and sholder..now and i have this pain all over my left side from head to toe(head,behind ear,neck,shoulder,arm,joints,knees,chest,abdomen,back) i had an ultra sound but the doctor told me i have normal breast tissue and no lumps even under the arm..could this be an advanced breast cancer? iam so concerned that it could be spreaded to lymph nodes,brain and bone..all iam thinking about is DEATH and am not gonna be there for my baby,,iam letterly going insane..plz help me.

[Cleveland Clinic]

Dear shareefa,  Breast pain is a common breast symptom.  The reason for breast pain is not clearly understood, and is not usually associated with breast cancer.  Breast pain is sometimes associated with hormonal variations and is then called cyclical breast pain.  Noncyclical breast pain does not seem to be linked to hormonal variations and is often localized to one area of the breast tissue.  Noncyclical breast pain may or may not be the result of an injury to the breast.   Over the internet without being able to evaluate including physical examination it is difficult to say for sure why you are having this symptom. You should bring your symptoms to the attention of your doctor who will evaluate in context.