How To Treat The Pain In My Groin Area And The Feeling Of Frequent Urination?

I have been having pain in my groin area for a few weeks now. The pain is in the entire groin area I was having problems with frequent urination but since starting antibiotics and flomax that has stopped but the pain wont go away. I have been to see a doctor a few times they have done blood and urine tests all come back negative for infection. They are saying it might be a bacterial infection that is just not showing up. I have been prescribed doxycycline and flomax. The pain started to supside but my wife and I had intercourse and when I ejaculated it hurt like it was too big to come out then my urethra burned and had a lot of pain in my groin the pain is less today but still has not gone away.