I have a h/o breast CA (IIDC) Her2 pos. diagnosed December 2010; followed by chemo, Herceptin, radiation, and mastectomy. I have had acute swelling and tenderness of right submandibular lymph node 3 months ago, and 2 days ago the same thing on the left. Plus, I have a lot of lower back pain and nothing seems to releive it except inactivity. Now I am also experiencing severe pain shooting down the back of my right leg when defecating. I get constipated and need to strain, and then I can't completely defecate due to this pain. I worry about mets to bone or something. Why am I getting these suddenly swollen lymph nodes and leg pain on straining to defecate?