an unpainful pea size lump for over a year under my left armpits

[Hanami]

i just turn 18 this year and i have a pea size lump under my left armpits.it has been there for a year already.but the lump does not hurt.my familly do not have any cancer history..so is it cancer...im so afraid...X<

[Cleveland Clinic]

Dear Hanami:  The general rule of thumb when a lump is identified is that it should be evaluated by a doctor.  That it has been there for over a year and has not grown or changed makes it unlikely to be cancer.  Further, cancer is very unlikely in an 18 year old.  Nonetheless, it may be a good idea to have a doctor do a check in order to get a baseline exam, help determine what this might be and give you some guidance for the future.

[Hanami]

A related discussion, Pea size lump under armpit since 2010 was started.