Uti now something else?

Patient: Hello,I had intercourse back in Jan. of this year and got my first ever uti. I was put on antibiotics and after finishing them the symptoms came back again worse then ever. Now for 10 months I have had a pinching feeling in my bladder with a feeling of pressure. Sometimes the pain spreads to my lower back. Out of about 20 urine cultures only 2 showed bacteria. I have been tested for std’s and everything is normal. Now I have just been left by my dr. as he is at a loss. I cannot sleep and get up to urinate frequently through the night. The symptoms are always worse after intercourse. Please help me. I cannot take this anymore and will do anything to find out what is wrong. Is a virus possible in the bladder?