Tender to touch spot under arm pit next to breast

?abscess/boil?: Get an eval to determine the exact diagnosis as it may be ab abscess requiring local I&D and/or antibiotic treatment, or a lymph node if on the arm pit area, needing further evaluation, etc. Best wishes.

Difficult to say: Difficult to say without a proper physical examination-see a doctor for a proper assessment if you continue to have pain.