Hello sir,
Thank you for your question and welcome to Healthcare Magic. I read your query and I understand your concern.
Let me say that you and your girlfriend have noting to worry about because non penetrative sex while on birth control pills
pregnancy is almost inexistent.
This is because of the two reasons you already mentioned, first of all pregnancy chances from precum are almost zero. However, there are rare cases in which living sperm can be present in precum, making conception possible.
I will not forget to mention the fact that you said that your girlfriend is under control pills, which makes again the chances of pregnancy almost zero. The only very small chance that your girlfriend to be pregnant is if she did take the pills regularly.
To sum up, both the factors that we mentioned make the pregnancy chances zero.
Regarding the symptoms your girlfriend is having, I would recommend her to seek a consult with the gynecologist, because my impression is that they are related to a
ruptured ovarian cyst, for which i guess she is having the medications.
Hope my answer helped you. For further concerns or follow up questions feel free to ask again.
Take Care,
Dr. Ina