Here u have told you have there is something called as pms. As per me the full form of pms is pre menstrual syndrome. Another thing you have told is you have already gone for hysterectomy in that case pms should not be possible with you. Now the next thing you are assuming is urinary tract infection. Lett me tell you urinary tract infection will have some more symptoms like burning micturation as well lower abdominal pain and fever. Kindly check do you have any symptoms like this if not then again it cannot be uti. There are different causes due to which person may have back pain some of them are back muscle weakness, spinal cord problem, disc problem, kidney stone etc, to rule out any of this you need to undergo for mri of lumbar spine as well ultrasound of abdomen based on the report you can visit specialist for detailed treatment discussion. Here there will be two ways of treating you the first way is medical managementhere if there is no major issue in your medical report then doctor will suggest you for certain medications along with physiotherapy treatment and back strengthening exercises this is called as conservative management for back pain. Now if there is good enough damage at your spinal level visible in mri report then here the orthopaedic doctor will suggest you for surgical correction. I suggest you can also use hot pack at home for some more relaxing effect on your soft tissues which will release your pain up to some extent. For UTI do not worry and visit your physician and take a complete course of medication as per his suggestions and you will be fine soon. take care.