I am sorry to read of you problem. From what you are describing it is difficult to determine the exact cause of your problem.
Interstitial Cystitis (IC) is usually associated with pelvic pain, pressure, or discomfort with persistent urge to void in the absence of urinary tract infection. While there are a number of diagnostic criteria for IC, there is no agreed upon gold-standard test that reliably makes the diagnosis. IC is therefore mostly a clinical diagnosis based on symptoms and signs, although, a number of tests are helpful.
It is unlikely that you have scar tissue unless you have had surgery or significant repair of the anterior vaginal wall after a vaginal delivery. Some patients do have areas that are trigger points for pain. These areas are tender under examination. Pelvic Floor Muscle spasms can be a source of pain as well but pain is usually more persistent and present with intercourse.
Given the complexity of this issue, I would suggest you seek an Urogynecologist or Gynecologist that specializes in Female Pelvic Floor Medicine and Surgery. You may find it helpful to visit http://www.mypelvichealth.org/ to find a doctor in your area.