Definitely better to be safe than sorry...
You should definitely see your doctor, as you can't make a judgment about these breast lumps (usually called cysts by doctors) on your own. If it makes you feel better, I have a history of developing cysts in my breasts. I'm over 40, so the standard for women my age is an annual mammogram; often I've had mammograms every 6 months to evaluate new cysts, and usually after a mammogram, they do a follow up ultrasound, which allows them to see the cysts in more detail. Twice my ob-gyn sent me to a breast specialist for an evaluation. Even after all of this, I've never even had a biopsy. Doctors are very skillful in determining whether a lump needs to be followed up, and they will keep a record of where your breast lumps are and track the changes over time. An ultrasound, which is totally painless, can also totally rule out cancer in most cases. They only do biopsies if the ultrasound isn't conclusive. A doctor's "mapping" of the cysts on your breasts should help you know when you have a new cyst or cysts that are growing. Even though I don't think you should worry, you really do need to see your doctor. One of my closest friends just had surgery for breast cancer, after putting off her doctor's visit for way too long. In her case, her self-evaluation was wrong, so it's better to err on the side of caution.
Hormones can play a role in causing lumps. Cysts can develop in the breast tissue. This issue really needs to be addressed by a dr. ANY changes in a breast should be looked at immediately. If you are having an annual exam with your gyno, he/she should perform a breast exam at that time. Regardless, an appt needs to be made to determine what the lumps are. At 35 most insurance covers a baseline mammogram if not a regular one annually. If there is anything suspicious, regardless of age, the insurance will cover a regular one. One in three women will get breast cancer. Early detection is life saving. Make an appt right away.