About 2 days ago an itchy lump appeared under the skin on my right breast, it's also red in the area....should i be concerned?

Only a little: Could be clogged follicle, infected skin, bug bite or various other things. You might try hot compresses and hydrocortisone cream. If you have fevers, severe pain, or spreading of the redness, or enlargement of the lump, you should be seen right away. This doesn't sound like a tumor or cancer but if it doesn't go away, that doesn't mean it's not important.