I ve pain on left side of tummy [on and off for 2 years],had sigmodioscopy,stool test all normal,ultrasound,omeprazole doesn't help;what could it be?

Left stomach pain: I have seen individuals with a vaginal infection w/ mycoplasma/ ureoplasma have such pain. i treat with Zithromax or Doxycycline and Flagyl ( if not allergic to these) and I have seen the pain resolve. Mycoplasma and ureo are normal in the vaginal tract but at times overgrow and cause pain. rare other entities, spigelian hernia, Meckles, check for H pylori. Constipation bowel gas, foods. f/u w/ do