Sue, I'm no medical expert, and please understand that no one can make diagnoses on this site. Only your mother's doctor can determine if your mother's case involves an infection, cancer or something else.   But, I can share what I was told when I went to a lymph node therapist for PT after all the nodes in my right armpit were removed following a mastectomy, and I was experiencing lymphedema.   If I recall correctly, there are lymph nodes spread all about the body - armpits, chest, neck, abdomen & groin.   I also know from problems that my mother had, that the nodes can swell, as they checked hers often and were considered to grow from large to extra large.  They thought she had lymphoma, but she tested negative for it.   Many things can make lymph nodes swell, as they collect bacteria and other agents.  Sometimes it's a precursor for something bad, and sometimes it's nothing (as they deemed in my mom's case). In any case it's worth getting more info from your doctor.   Hope my insight from personal experience helps a bit & that things turn out well for both you and your mother. Please check in with your mom's doctor and keep us posted.