I have large pea size lump under armpit for mths. it has got slightly bigger..it moves -armpit sore sometimes. dad/2 aunts/&2 uncles -cancer.im 50?

Get seen: This may be anything from a benign epithelial cyst to an infected hair or gland to a benign reactive lymph node (my guess) to something worrisome. No one here can really tell you much more. At your age the only malignancy that is at all likely to present like this is Hodgkin's, and this would be unlikely to progress this slowly. Get seen when it is convenient.