What Causes Frequent Urination And Lower Back Pain Worsening When I Need To Urinate?

Hey i have been treated for uti 3 times in the last 4 months, just finish taking antibiotics about a week now and am beginning to have frequent urination again and a pain in my lower back which get worst when I want to urinate, there is no pain when I urinate the quantity is the same and the colour has not change it s still pale yellow, I stated having metallic taste in my mouth today, can you tell me what s wrong with me and the steps to take from here on. Thank you