breast canc. left breast 2004.chemo,radiation. 8 mos ago banged same arm above muscle. Swollen area developed over arm muscle and is still very swollen to date. Recently hit the same area and area was very tender for 4 days . could i have Lymphoderma 5 yrs after breast cancer? What else could this be and why wont swelling go down after 8 mos.?