Pain and leakage from the breasts could be due to the end of the pregnancy but I'm not sure about possible causes for the lumps you're experiencing under the arm. You'll need a physical examination (inspection and palpation) to identify and diagnose the lumps. If they are under the skin, they could be lymph nodes and then could be related to an occurrence in the breasts. That “something” can be revealed only with a physical examination (inspection and palpation) and an ultrasound. If these diagnostic procedures indicate something new, then further diagnostic steps will include a mammography and fine needle biopsy, if necessary.