TTC for two months need advice

Hello, so I ovulated the Monday 8/24 and on and off I have been having very sensitive nipples. Like they hurt to wear a bra or touch anything. Any ideas from future or current preg moms? Also I'm confused on the most fertile day according to glow and when you ovulate. My doctor told me my most fertile time is the first three days before ovulation. Is it still effective to bd on the most fertile day according to glow. So sorry for all the questions just trying to understand this app