Breast lumps from bruise?

About a week ago, I discovered breast lumps in my left breast, right where the contour starts.  They're about medium sized, don't hurt, but are hard to the touch.  There's 2 of them.

Also worth mentioning, 3 weeks ago, I was in a car accident.  The seatbelt wrenched against my left breast, and created a very large bruise, about 3 inches wide by 9 inches long.  It faded completely about 5 days ago.

I was told that the lumps could have been a result of the clotting of blood in my muscle, because they are right where the bruise formed.  In fact, when the bruise subsided, it seemed to subside the fastest around where the two lumps are.

I have never had problems with breast lumps, and I do check to see if I do when I think of it.  I admit I don't know when I last checked for breast lumps before this occurence, but they're noticeable enough so that if they aren't a result of this trauma, I'm surprised I didn't pick them up.

I'm 25, obese, and exercise regularly (3-5 times per week).  My mother has trouble with fibrous tissue forming in her breast, and it's caused a couple of scares (luckily without any malignancy).  She's 53.  My great aunt is the only one in my family that has had breast cancer.

My question is, should I be concerned about these lumps?  Should I wait a little while longer to see if they disappear, or should I get them checked out immediately?

Thanks in advance!

[CCF-RN,MSN-JS]

Dear nickel, These lumps could very well be a collection of blood from the bruising, especially since you have noticed them in this time span.  If this is the case they should resolve on their own over time, and that time could be weeks or a couple of months. Waiting to see if they get smaller or disappear would be up to you in terms of your level of comfort with waiting. Without having them evaluated there is no way to be sure at this point whether these are a consequence of the bruising from the accident, or from another cause.