Research has shown that breast self exam (BSE) plays a small role in finding breast cancer compared with finding a breast lump by chance or simply being aware of what is normal for each woman.
A great way to get to know your breasts is in the shower when you are all lathered up with soap. By touching them naturally, you get to know how they feel and what lumps and bumps are perfectly normal. Besides touch, you can also visually look at them in the mirror so you can see what they normally look like.
If you are comfortably doing a BSE, then by all means you should, but if you aren't comfortable or it stresses you out, don't feel guilty about it. Find a way to just know your breasts that makes sense for you and then you'll know if anything changes that would warrant a call to your physician.