Sore nipples

I’ve been EBF for 5 months now. I have flat nipples and so at the beginning I had really sore nipples. It was hard powering through and then as soon as it started getting better, we ended up getting thrush. I had to really power through that. Now that we’ve gotten rid of thrush I’m realizing that my nipples stay sore all the time. It’s not excruciating like thrush or the beginning of breastfeeding but it’s still sore. And they stay really pink. It’s not his latch. We’ve mastered that. So I’m wondering if it’s normal to still have sore and pink nipples 5 months into breastfeeding? Could it be because I have flat nipples? Should I be putting something like lanolin on it?