I had sentinl node biopsy and lumpectomy 6 weeks ago. i developed a seroma unde my right arm... I had pain under that arm that got so bad I went to the ER. Ehen I raised my arm to show the er doctor the lump I could have died from the horrible sharp I got in my armpit. It felt like someone shot me right in my armpit I screamed in pain. No one told me that I should not raise my arm over my head for the first 2 weeks after surgery. I cant reach for anything upwards or downI can extend my arm out in front of me but cant turn it over with my underarm facing upwards while it is extended out. Please help me.. I dont know if i tore something or there was nerve damage from the surgery and the cutting in my arm.. I dont have numbness or tingling I just cant stretch my are without terrible pain...Thank You