you should do it
While there is no proof that breast self-exams reduce your risk of dying of breast cancer, studies have shown that women who conduct self-exams tend to find growths that are much smaller and less advanced than those found in women who do not. Since self-exams don't do any harm and take only a few minutes, why not get into the habit?
You're looking for any unusual lumps, dimpling, or thickening in the breasts, as well as discharge from the nipple or any other abnormalities.
Start by looking at your breasts in front of a mirror, first with your arms at your sides, then raised over your head, and finally, with hands pressed on your hips, flexing your chest muscles.
Next, examine your breasts in the shower, keeping your fingers flat and moving them over each breast. This can be done in a few different ways -- in circular motions, pressing gently every inch or so and moving closer to the nipple with each circle, in long, vertical strips, or moving in toward your nipple like spokes on a wheel.
Finally, lie down with a small pillow under the shoulder of the breast you will examine. Put that hand under your head. With your other hand, examine your breast in the same manner as above. Repeat with the other breast. Gently squeeze each nipple to check for discharge. It's important to feel under your arm as well.
Most lumps are not cancerous, but only your doctor will be able to determine the nature of yours. For more information, talk to your doctor.