When was the last time you had a GYN exam?
I ask, because if you're nursing a vaginal infection, such as a yeast or bacterial infection (and/or he is), it's very common to have burning or stinging with intercourse or other sexual activity.
So, take care of that first -- get in there and make sure you're healthy. If you are, I'd also encourage you to start using condoms so you both can STAY healthy. Being screened with negative results for STDs and STIS means only this: that at the time of the screening, you did not have any active STDs or STIS which CAN be tested for (mind you, some of the most common can't be tested for accurately without symptoms, like HPV and genital herpes, which in men can't be accurately screened for at all much of the time -- but your clinician or doctor certainly would have mentioned this at your boyfriend's last screening).
If you aren't presently nursing an infection it could be a semen allergy, or could be a matter of a lack of lubrication.
Editor and Founder, Scarleteen
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