Burning Pain in Urethra

I am a 28 year old woman. I have been in horrible pain for the last 2.5 years, and I think it may be getting worse. I am looking for answers to what might be causing the pain and what treatment options I have.

Symptoms:
1) Burning in my urethra. (negative for bacteria, stds, cancer, kidney stones). The burning can be light and last for hours or very intense and last for 20-35 minutes. I haven't found any pattern. Urinating can be a trigger but is not always a trigger. The burning is usually worse in the evening. Most days I have some level of burning. I have no urgency, frequency or bladder pain.
2) Pins and Needles (sometimes right before or right after burning).

Possible Clues:
It feels like the burning may be at the neck of my bladder. I was told I might have IC and tried Elmiron (did not help). The catheter burned like crazy when pushed into the bladder. I have also been told I have nerve pain related to recurrent UTI's. I also was taking Macrobid long term and have heard that that could have caused this pain.

Other information: I have Crohn's Disease and Rosacea and am currently on Remicade and MetroLotion.

I am looking for answers to the following questions:

1) Assuming this is nerve pain, will it go away?
2) Are there any other ailments that resemble the pain that I am feeling?
3) What do you treatment options do you recommend?

Please help - the pain is getting worse lately and I am feeling very desperate. Thank You!