'Chronic' means present for a long period, 'uretheral' means related to 'urethera', which is the tube connecting urinary bladder to the exterior and 'obstruction' means that there is hinderance to the outflow of urine. The pain / discomfort may be due to the dilated urinary bladder (as it cannot empty itself fully) or due to infection (which tends to occur in stagnant urine) or due to the causative factor (which could be stricture, stone, cyst, tumour, inflammation or the drag because of prolpse of uterus or vaginal wall). I think your mother requires a clinical examination by a urologist and a gynaecologist. She would require some investigations including urine examination (routine test and culture), Ultrasound examination alongwith post void residue and a uro-flow study. She may need a cystoscopy for further evaluation, depending on the results of the investigations. Proper treatment can be planned only after the above evaluation.