Kidney stones are salts of many minerals combined together which get deposited in urinary tract ie kidney,ureter, rarely even urinary bladder. There are many reasons like consuming foods rich in oxalates, dehydration, certain medications, obesity. Symptoms include flank pain, nausea, vomiting,fever, blood in urine. Kidney stones can be diagnosed by ultrasound of abdomen. Usually small stones less than 5mm pass off without causing symptoms. Stones more than 5mm can cause obstruction if present in ureter and thus can pain.pain can be severe if stone is passing down. Usually less than 10mm stone wit no symptoms can be treated conservatively by taking more fluids so that the small stone passes in urine. If stone more than 10mm wit symptoms then definitely surgery is the treatment. Many surgery options are there depending on stone location,type of stone n size. Prevention of stone formation include having more fluids, avoiding foods rich in oxalates like spinach, rhubarb and avoid calcium supplements, reduce weight.
Dear madam since you have stone of size 13mm with pain I suggest you get surgery done. I suggest you to consult nearest nephrologist soon.