Do parasites move from body part to body part?!

Can intestinal parasites like worms, flukes and amoebas move to vagina without having anal sex? Can they live in vagina? What would syptoms be? How do they get discovered? Sorry its nasty....but I I am trying to figure out if they would cause BV or other disease in vagina? Something has to cuase the pain and burning. So far was tested by 2 Dr's 6 times withing 4 months.....No STD, no BV, no Yeast, Herpes were found. NO smell, no discharge, and no I had no anal sex. All good hygiene, no tampons, boiled my underpants even, showers daily warm water, 4 months of this horror, so NO I didn't have any sex at all for 4 months. Dr has no clue. NOTHING found by swabs. My vagina hurts and burns (no inside thou) Outside, or at the opening. No sores, no bumps. Skin is ON FIRE and red as h..l. HELP....parasites maybe crawled in there?