Doctors found a 10mm cyst on my mammogram/ultrasound. and have increased my birad to 3 rather than 2. does this mean i have cancer?

NO, probably NOT!: Most beast cysts are benign. BIRAD 3 means it is probably benign but there is a small (about 2%) chance it is cancerous. It is usually advised to recheck in 6 months. See https://breast-cancer.ca/bi-rads/ and also see https://thetruthaboutcancer.com/breast-cancer-prevention-tips/

No.: A cyst is a benign finding, usually assigned BIRADS 2(benign) and requiring no follow up or treatment. Sometimes a cyst doesn't fill all the criteria of a "simple" cyst, and is described as a "complicated" cyst. Occasionally the radiologist might assign a complicated cyst a BIRADS 3(probably benign) and recommend follow up. By definition, BIRADS 3 implies a less than 2% chance of malignancy.