tl; dr: Yes, I had nipple pain. Yes, it went away, but it took a while. Yes, I'm still nursing.
My nipples were SO sore I was convinced I had thrush. About two weeks ago (30wks) the pain suddenly vanished. DS was about 20mos when I got pregnant. I did discourage "boredom" nursing, and at times I just said no when the pain got to be too much for me. We are still nursing, however. He nurses less, now, but he's also over two, and I think that's normal regardless of whether I discouraged it.
I work part-time nights and go to school full-time, so I had some natural respite periods built into my schedule. Taking the 16 hour breaks sometimes really made a difference. If you're home with your kiddo all day, it might help you to limit nursing to naptime and bedtime, and for "emergencies" (falling down, doctor visits, etc). You don't have to feel guilty about this, because in approximately 35 weeks you're going to be saying "no" to nursing sometimes anyways, because your newborn will have priority on the milk.
The biggest criticism I hear when I share with "mainstream" people that I'm still nursing my now-26mo is that they've seen older children walk up to their mothers and lift up her shirt without asking. I don't know how other women feel about this, but I feel it's important to teach my son limits and boundaries. Yes, we can still nurse, but you have to ask (and use manners!) and sometimes it will be inappropriate and I will say no, just like I would say no to another cookie, or an extra cup of juice, or a flashy toy in the grocery store. I think we are sensitive about it because it's such a special bond we have with them, and we're worried that saying "no" to nursing is somehow saying "no, I don't love you." and that's not the case. Which isn't to say that DS didn't get really upset when I said no to the nursing, but I would distract him with something else, or, if he was absolutely single-minded about it, DH would distract him.
Anyways, that's my take on it, and we're still happily nursing, so you can take whatever you want from that.