Orgasms are great pain relievers. Tolerance to pain (capacity to endure pain) is also at its peak during ecstatic foreplay.
What appears likely is there was a stretch, jerk or pressure on the cervical spine
while at foreplay due to some posture.
If this never recurs (most likely it won't) not just during foreplay, but at any other time then body has healed it.
This is not caused by or due to orgasms.
Feel free to ask if you have additional questions.
Dr. Ashok Koparday