What Causes Frequent Urination And Discomfort In Lower Back?

i tend to urinate very often and seem to urinate much more than i ingest. at times i feel discomfort on my left and right sides of my lower back. i do have hypertension and take a medication with a dieuretic but this problem just started about a month or two ago. i drink plenty of water as i do not drink soft drinks or any other drinks containing caffiene or sugar. i am a forty nine year old male( soon to be fifty) and exercise with weights a minimum of twice per week and am considerably in very good shape for my age thank you bill