Hi. Thanks for your query and an elucidate history. Severe lower abdominal pain can not be due to acidity; it causes upper abdominal pain. Secondly, your pain is severe and not associated with the menstrual cycle. The most probable causes of a severe pain in lower abdomen which takes breath away can be due to: Twisting of the ovarian cyst. Lower Ureteric stone. Volvulus , meaning twisting of the intestine along its own axis. I would advise you the following in such conditions. First of all get a X-ray of the Abdomen in the standing position. This is the simplest form investigations giving the maximum information particularly when you are in a pain. Ultrasonography, blood and urine test will help for further diagnosis. The treatment will depend necessarily upon the diagnosis one gets.