I’m 21 years old and recently (7 days ago right when my period ended) i got a hard sore lump under my left breast and it was painful at first but not anymore. the lump seems to be deeper in my breast tissue because i can’t see it but i can feel it. i felt a dent right underneath as well but i never looked at it until today. i have gotten breast lumps before that occur with my period and they usually disappear but this one has not and it’s been 7 days now. i already have HORRIBLE anxiety and noticing this dent has made me extremely worried and i can’t calm down!!! my heart is racing. i haven’t spoken to my doctor yet but i plan on doing so soon. i don’t have any family history of breast cancer. I am extremely terrified that this will turn out to be breast cancer.
Hi Allison_2000 firstly well done you being vigilant and keeping aware of changes. Do make a doctors appointment, it is always best to get any changes immediately checked over, also do not be fobbed off by your age or patronised in any way insist on a referral, that way you will have peace of mind. Early detection if there is anything going on will enable your team to take care of you. But please do remember till a professional tells you, you have breast cancer, you do not have breast cancer. But please do go and get seen by your doctor and a referral. Please let us know how you get on 
Shi xx
Hi Allison,
If you are used to tender lumps appearing with your monthly cycle, then its a high chance logically (as this one was there at the end of the period) that its the same thing and caused by hormonal changes. They do say to not do breast examinations until one week after a period ends, which is when you did it, but I have heard that resolution can take longer than that for some hormonal changes. I know you are saying that it has been 7 days now and although the pain is diminishing that the ‘lump’ still can be felt, but it does sound like it came up very quickly and of course that wouldn’t be something consistent with BC, and pain diminishing in a good sign too. You are also incredibly young, of course that doesn’t make the chances zero that BC could occur, but it certainly makes it statistically very likely there are benign causes for the symptoms you describe. There are so many benign causes for the types of symptoms you describe, but of course those don’t really get talked about, and at the clinics those are the main findings for women being referred.
As you are so very anxious, I certainly agree with Shi that someone putting your mind at rest would be a good idea. Often at surgeries the practice nurses can take a quick check and then send you on to the Dr if they think there is any reason for further checking. Panic attacks are horrible things, and I can see how scared you are, but honestly I think a quick ‘once over’ sounds like a good idea. Even IF you were referred, that also doesn’t mean BC, it just probably means the Dr is being ultra cautious and thinks some imaging would be a good idea to have some clarity. You are clearly very vigilant and it sounds like you do monthly checks, but it can be difficult at your age to know what is ‘normal’ and ‘abnormal’ during your checks, as tissue is still hormonally reactive - so get a wee bit of help on it I think 
x