Hi, I have gone through your question. I am a practicing anaesthesiologist and pain consultant. As per your question, you are having left sided back pain. If such patient comes to me, I would consider the possibilities of--- 1) Urinary tract infection - infection to kidneys, ureter or bladder 2) Kidney stones 3) Gastroenteritis - infection of stomach or intestines 4) Dehydration 5) Spine related problems 6) rarely appendicitis 7) sprain and many other rare causes I would like to know, whether you are having other symptoms like fever, nausea, vomiting, blood in urine, diarrhea, constipation etc If you are having any of the above symptoms, better to visit physician and get investigations done. If nothing, then simple pain killers like paracetamol and tramadol will help you