Vaginal pain & scarring?

Im a 20 years old female. I am STD free. very clean. have had the same sexual partner for 4 years and is the father of my child. i had 1 abnormal pap smear and that was when iwas 16. i had pre cancer cells on my cervix. they froze and cut them off and every pap smear i had since then has come back normal. I have two year old son. while i was pregnant with him a started having sharp stabbing pains in my vagina at random times. they would only last a few seconds. after i had my son, these pains continued. after two years i continue to have them. i also i had quite a bit of tearing when i was giving birth to my son. it took a while to heal. but two years later i went to doctor because of these sharp pains and she said it was from all the scar tissue. i sometimes experience pain during intercourse which she also blamed on the scar tissue. after two years i would think that a SCAR wouldnt cause any problems. she didnt give me a prescription for anything so im assuming nothing can be done about it. i also suffer from VERY frequent urinary tract infections since i was a small child. as soon as i get rid of one a few days later its back. i drink plenty of water and cranberry juice and avoid baths. idont know if the UTI's have anything to do with the pain or not. ive also researched symptoms of pelvic inflamitory disease and im beginning to think i may have that. any suggestions or advice on what to do or what this could be would be MUCHLY appreciated.