A few weeks ago a study stated that self-breast exams didn't save lives, but I am not buying it. Many women I know have caught their breast cancer early because they did monthly exams. So if you're still a believer and continue to check yourself monthly, you should be reassured to know that most lumps you find aren't cancerous. Here's what you may feel according to Living.Health.com:
A soft lump: It's smooth and round (like a grape), and it moves a little when you press on it. This lump may be painful to the touch, and it can range in size from small to large. It could be a cyst or sacs filled with natural fluid, but you should get an ultrasound just to be sure. If it is a cyst, your doctor may recommend that you go on the Pill to lower your chance of developing cysts.
A hard lump: This will feel like a clearly defined smooth, hard, rubbery, round lump. It could be small like a pea, or up to five inches wide. If you can move it around under your skin and it doesn't hurt, then it sounds like it's a fibroadenoma, which is a noncancerous tumor. They're not as common as cysts, but not uncommon for women in their 20s and 30s since they're caused by hormonal changes. Of course, it's best to have your doctor take a look and perform some tests just to make sure.
To find out what else you may feel and what it means
Fluid: If fluid is leaking from both nipples, it could be cause by a thyroid or pituitary problem. Talk to your doctor and if it is a gland issue, medication should clear it right up.
Soft mass: You could feel a soft lumpy mass that's about one to four inches wide, and it may be tender right before your period. It most likely is caused by fluctuations in your hormones, which thickens breast tissue. This isn't anything a little acetaminophen or ibuprofen (or chocolate) can't take care of.
Hard Mass: If you feel a solid, irregular shaped mass with jagged edges that won't move when you push on it, this is something to be concerned with. It could be a cancerous tumor so call your doc and schedule a mammogram.
Fit's Tip: This info isn't meant to scare you, but since you are the one person who can notice changes in your breasts, it's best to know what to look for. If you ever have any concerns, I'd recommend seeing your doctor because you'll feel relieved to get a professional opinion.