I have a pea sized lump in the armpit area. It is painless and immovable. Could this be a sign of cancer?

Must see it! I would love to be able to reassure you but this requires evaluation by your doctor as my initial thoughts could be a cyst, an abscess, a hair follicle granuloma, or an enlarged lymph node which may indicate an underlying concerning condition. Please get it checked if it lasts > one month.
Concerning. It is certainly concerning for being cancer. Please consult your doctor who can order appropriate tests and biopsy.