Maybe it's pelvic infection

Yeah you are ESR is very high along with low-grade fever which indicates towards tuberculosis but you have not elaborated your history like is the fever present throughout the day or is only present in the evening or there is the evening rise of temperature is there any loss in the body weight or decreased appetite. Lower abdominal pain cannot be due to acidity issues acidity usually causes epigastric pain in substernal burning sensation so maybe one of the reason you might be suffering from abdominal tuberculosis Or some infection in your large intestine. Hello ESR is a very weak market but in the presence of fever it in specifically point out towards some diseases