Dear S.,
Over the last 7 years I have had this happen to me 3 times. Each time I get a run of test done & everything comes back normal.
I have been to OBGYN (started here as I do has PCOS) & ruled out cysts (I do know what that feels like & it is not the same) a general Phys, gastro intestinal, ER, had ultrasounds, blood work, CT. All come back normal except a very slightly elevated white blood cell count which quickly returns to normal. I also have had low grade fevers but of course by the time I get to the doctor it is back to almost normal (I have a low body temp to begin with so that does not help me when I am at the doctor & tell them my temp is elevated & they say it is almost normal).
Eventaully it goes away & I am fine. The only thing thay all keep saying is it sounds like my appendix but the tests come back normal. After the 3rd time I had this occurred I talked to my aunt & she said that she would have the same problem when she was younger & after several years her appendix did burst. After it was removed the doctors asked if she had had problems with it before as her appendix showed scarring & signs of periodic flare ups.
The only thing that we could determine is that possibly my appendix is flaring up but my body is fighting off the infection good enough that blood tests are good, temps is mostly normal & it is not inflammed enough to show on ultrasounds & CT scans.
The only thing that the doctors told me the last time was that to really detetmine what was the problem they would have to do exploratory surgery & I am not willing to do that.
If the pain continues try a different doctor. Get copies of all of your records & make sure that every doctor & specialist knows what the others have done & recheck their work. I hope you can determine what the problem is. Good luck!