Urine pain & Burning after periods. Do?

After completion of periods, I get unbearable urine pain, burning sensations, continuous urine backache & body heat. Also, last year twice periods got missed, I also consulted best doctor also but he said it is a UTI symptoms and also I did diabetes & thyroid test which is normal but I do have baseline thyroid after doing test. Even my weight got gain due to this I guess. He asked me to drink water a lot, do exercise, weight loss and eat healthy only. Periods are getting regular now but still after 8-9 months again today I am getting such symptoms like urination pain, backache, burning sensations while urine & again & again urine It's unbearable while urination But why it is happening mostly after periods after consulting and having medications also why it is not getting stopped for once & all. Please help whom to consult the correct doctor & what to do?