what's this deep itch in left side of chest/back & numbness that i'm feeling?

[jamie0304]

i'm a 20 year old female and i've been experincing these symtoms for a week and a half. the left side of my chest, right above the breast feels like theres a deep itch that i can't scratch -- as if its on the inside. when i do scratch i feel discomfort and just numbness. the itch and numbness spread to my upper left arm (more towards the armpit) and also to my upper left back.

i've been tring to feel for a lump on my left breast but its difficult to tell because of the numbness. it does feel like theres a slight bump (but i'm not sure if i'm just imagining it) that when lightly pressed the itching sensation is triggered.

the itchiness isn't there all day, but i feel it for maybe a few minutes at random times or if i accidentally scratch the affected areas. i haven't done anything out of the ordinary of my habits. i do work very late into the night like until 5AM but ive been doing so for the past 3 years and havent felt sick from doing so.

please help.