Surgical changes or something else

Swede

Hi everyone. I am approximately 10 months post lumpectomy with SLND (positive for macromets), 6 months post chemo, 2 months post radiation and have been on AIs for 2 months. In the last week I have noticed increased swelling, warmth and tenderness in the affected breast, and slightly reduced range of motion of that arm as well. Today I noticed a small pea-sized lump at the SLND area which I do not remember being there before. However, before, the SLND area was not tender so I was not feeling around. I have a call into the doctor, but in the meantime, I am wondering what you think? Is it likely that I am feeling a lymph node or new tumor? Can my symptoms be caused by something else? My anxiety level is really beginning to rise. Thanks in advance.