If the semen was not in contact with labia or vagina then less chance of getting pregnant although pre-ejaculate
or pre-cum also has sperm. Since you are on birth control, nothing to worry.
Also since you got your period there is no chance for pregnancy
Sore breasts could be due to a condition called Fibrocystic disease
, especially if it occurs during many of your cycles. This is due to hormonal
changes in menstrual cycle. You may consult your Doctor about sore breasts as it needs clinical examination. Certain medication may help. Eating Soya also reduces it. You can take Paracetamol
under medical supervision for pain relief.
Kindly practice safe sex. Use condom to prevent pregnancy and sexually transmitted diseases.
Wishing good health.