A needle biopsy is usually done in the doctor's office with a local anesthetic.  If your work involves lots of lifting and using your arm, you should ask your doctor how soon you can go back to work.  However, you can probably go back to work right away if your work is less physical.  You won't feel anything when the biopsy is done because of the numbing medicine.  Later you may have some aching when the anesthetic is cut off. If your fear is mainly related to worry that the biopsy might show you have cancer, you should know that the vast majority of lumps that need a biopsy turn out to be benign.