October is national breast cancer awareness month. As a breast cancer survivor myself I encourage you to do a monthly breast exam. I found the lump in my breast as is generally the case. The hope is that a lump will be found early, when the tumor is small and less likely to have spread.
If you have not reached menopause you will want to do the exam a week or so after your menstrual cycle to avoid the lumpiness that is often due to hormonal changes prior to the menses. If you no longer have a menses, any time of the month is fine so long as you remember to do the exam.
Using the pads of your fingers, gently palpate your breast in concentric circles until you've examined the whole breast. Normal lumps generally feel like grapes. If you have a lot of lumpiness that is not abnormal. It can be frustrating though and worrisome. It need not be. A lump to be concerned about will feel like a rock....think of it as feeling like a rock in a bag of grapes.
All women are at a high risk for breast cancer and the fact that you have no family history should not discount any concern. As they say in sports, the best defense is a good offense, so be proactive and look for those lumps...if you find anything that concerns you, go see your doctor. It is better to be safe than sorry.
You can also examine your breast in the shower. Put some soap on your hands and as you wash your breasts using your hands you will be able to feel any abnormalities. I found my lump this way.
An ultrasound can deterimine if a lump is solid or fluid filled, which would be the case if the lump is a cyst. Any solid tumor must be biopsied for a definitive diagnosis. Breast biopsy is no big deal...it can often be done in the surgeons office with a local anesthetic. As Jeff Foxworthy say "just get er done". Don't let fear rule you and put off getting a definitive diagnosis...it could be a matter of life or death.
If you find a lump, don't be paralyzed with fear and don't bury your head in the sand. Call the doctor, make an appointment, and then put it out of your mind until you see your doctor knowing you are doing all you can do, and knowing that early detection is a great help and hope for cure.