Yes, breast cancer CAN run in families, but it doesn't have to. It does certainly increase your risk for getting it, and that is something you must tell your doctor (it would not hurt to tell your dictor this each and every time you see him/her, just as a reminder).
If you have any concerns, you need to find a good doctor; it can be a family physician or a gynecologist, or even a gyne/oncologist. And since you have concerns, you should not put off your visit to your dictor. If you don't like the one you have, ask your friends and family for who they do AND DON'T like! You will find that most women will not mind sharing information about this, and you may also find a large support network out there (just like on this board); it's just good to also have a network you can reach out and hug, too.
Write down all the questions you can think of for your doctor; think of things to point out on your body, different ways you have felt (or things you have seen) from what is normal for you, etc. And write down what your doctor says (make sure you get the spellings right). It may help to take along a trusted family member or friend to help you do this. Yes, it can be hard to take care of your body.
I have gotten into the habit of keeping notes on each member of the family. I make an entry of the date, the amount I pay, the doctor/pharmacy/lab/etc. seen, the general reason for the visit, and the diagnosis. I write the name and dosage of each prescription (and any allergic reactions I might have). If it's something complex, I also keep the notes I've taken to the doctor's office. Or if I notice something odd, like I start to run a slight fever for a few days, or my periods were different in some way, but I don't see the doctor, I might make a note. Over the years, I have found this to be helpful, especially for my problems, which have been more on-going than the rest of the family (thank goodness we're not all afflicted). But for my kids, I now have a record of when they banged their heads real hard or sprained a finger, or whatever, and this may help them make sense of any symptoms they get down the road.
Please see a doctor soon. Do not be afraid of having cancer, and do not put off seeing a doctor because you are afraid of the diagnosis. IF (and I stress, IF) you have cancer, the sooner you see a doctor and get a diagnosis, the sooner you can get help and the sooner you will start to feel better and begin to get on with your life.
A better place for you to post any cancer concerns would be under the Cancer; Breast, Cervical, and Ovarian. There will be more people who can directly address your concerns.
Good luck in your decisions, and I hope you get some answers very soon.