Chronic pain! Desperate for some relief. I'm not sure what's happening or how to fix it. Please help! Sorry long post!

Hi all, I have experienced recurring UTI and general vaginal sensitivity for three years now. My OBGYN suggested an Antibiotic after sexual intercourse (I know!) and an estrogen cream (I'm relatively young and wonder why I need estrogen cream). Most recently after remaining abstinent (too afraid to have sex or wear the wrong underwear for that matter) I decided to have sex and am paying for it dearly. Lots of UTI symptoms and pain even with the Antibiotics . Went to the doctor thinking I had yet another UTI, but I don't! This has happened before and they usually throw Antibiotics at it so I'm wondering just how many were UTI and how many just felt like UTI. I have had STD screenings, pregnancy tests, and ultrasounds (all negative). No one can tell me why I have UTI symptoms with no UTI! Even after a full course of Antibiotics , I'm still in pain. I'm taking Ibuprofren in case it's inflammatory but it doesn't appear to be working. Perhaps something is irritating the bladder and urethra but what? And, if it's not a UTI, what do I do to fix it? Are there things that can stop the bladder from spasming (I think this is causing the symptoms). Oddly, though I'm testing negative for UTI, my white blood cell count is moderately high (even with antibiotics). I prefer to try to approach things naturally but I've been in so much pain throughout the years (and especially this most recent incident) that I finally gave in in an attempt to just make it stop! Is there anything I can do for immediate relief? I've heard baking soda in water....does that apply to me? I've heard good things about mms, and nettle tea. I'll do anything it takes to get my body back on track. Hopefully whatever I do will help the general vaginal sensitivity I've experienced as well. Sorry about the long post! I hope someone can help! ANY advice is appreciated.