Swelling of lymph nodes in armpit.

1 yr ago my mom had swelling of lymph node in right armpit and  it was painful  intially she took medicine for infection but It got worse over time and did fnac, mammogram( which shows right axillary lymphadenopathy and no left axillary lymphadenopathy)USG sonogram  and lymph node biopsy  and done culture test for tb also  and report shows  she has no tb and cancer  and after 6 mnths  she took 2 nd mammogram  which shows that her right lymph adenopathy is completely cured Now she has swelling in left armpit  she noticed 1 week ago But it is not painful  Whether painless swelling may be a cancer? Kindly help me with is problem Do we need to  do test in left armpit also? Can adenopathy spread to another hand also?   Can we get cancer even after 2  negative mammogram (6 mnth interval) (She is a diabetic patient ,has bp and done merina treatment 2 yrs bfr  and didn't remove coil yet, she is 51 yrs old) Kindly tell me whether it is cancer since the swelling is not painful?