I'm preganant and have gbs. Can this cause pain and burning during sex? If not, what else can be causing this?

Group B Strep. Group b strept infection/colonization of the vagina does not usually cause any symptoms, which is why it is necessary to screen every pregnant woman for it. The causes of pain and burning during sex in pregnancy are pretty much the same as when you're not pregnant: vaginal dryness, vaginal infection (yeast, trichomonas, bacterial vaginosis), urinary infection, or sensitivity (latex, etc.).