just last night i was checking my breast and under my armpits for lumps..like i do once a night every month , but when i was feeling my left armpit ..right above where my hair grows ..there's this huge lump there kinda feels like a little hill..and its got me worried , it only hurts when i push on it and when i do, i feel a lot of little pea size bumps ..but it doesn't hurt ..unless i push on it ..i'm scared because cancer runs high iin my family ..my grandma , my uncle and my aunt has all han cancerous tumors under their armpits,when i run my hand over it it feels like a small hill..then when i feel on it it's like small little bumps are in it , i'm confused cause i don't see the lump when i look at it in the mirror ...please help me to understand what it is .?