To answer your questions:
Pain associated with interstitial cystitis may be due to abnormal bladder epithelial permeability. As the bladder wall is healing, it should result in a reduction of pain.
It is unclear what exactly causes interstitial cystitis, although stress seems to exacerbate the problem. I am unaware of consensus studies suggesting that removing acid can help.
Elmiron is a urinary analgesic used for interstitial cystitis. The optimal treatment is unclear, and there are no studies that demonstrate that Elmiron works in everyone. However, given the lack of any other clear treatment options, it would seem to be a reasonable choice.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.