Thanks so much for your replies, everyone. I really appreciate the help. Thanks in particular to craft_media_hero for all of your detailed advice.
The LCs that I've tried both came highly recommended - I guess that perhaps I need to be more assertive in going back for more help. They both worked on my latch, but it didn't really hurt less even when they latched her on themselves, so I'm not sure how to get her to latch on "better." As far as I can tell, she has enough of the nipple in her mouth, and it is the right shape when I take it out.
I have been basically walking around all day with my shirt unbuttoned, and I have tried expressing a little milk and letting it dry, and then applying ointment (I haven't used lanolin b/c I'm allergic to wool, but I've been using the Earth Mama Angel Baby ointment that came recommended on online boards from other moms with a wool allergy). This hasn't seemed to make any difference though, other than the fact that the ointment at least keeps the air off the nipples, which reduces the burning when I am not nursing.
I have read elsewhere that changing the nursing position may help, but I'm a bit nervous to try this - I have been focusing so hard on trying to get the latch "right" in the standard position (using a my brest friend pillow plus lots of other pillows/towels for propping her into the exact right position), that I don't know how to make other positions work. I was originally trying lying down nursing at night, but had to quit b/c it became even worse than the other position. The nipple pain for some reason seems to be the worst at night (but this is true also with the standard sitting up position), so maybe it wasn't the position that was the problem, but I just can't tell.
In fact, if I just let her latch on however, it doesn't seem to make a difference - it seems that almost all latches hurt the same amount. I've tried massaging the breast while she feeds, and also supporting the breast in various holds, and I'm not sure that this doesn't make things worse...
The LCs did check her for tongue tie and didn't seem to think that was an issue (or if it is, it is very minor). She may not be sticking her tongue out enough, so we have been doing tongue exercises, but I just can't tell if I'm doing them correctly, and they don't seem to be helping. No one mentioned anything about a high palate - it doesn't look high to me, but I have no idea what is normal for a newborn.
Thanks for the recommendations on the nipple twist - I will try this next time I feed and see if it helps. Thanks also for the cream recipe recommendation - when the pharmacies open on Monday, I will try to obtain some of this asap. I have wondered about thursh since I have always been prone to yeast infections and I had to have IV antibiotics during delivery b/c of positive strep B results, but neither LC mentioned it as a possible cause and the baby doesn't have any symptoms, so I'm not sure if I should push to see if this could be the problem?
I had a nipple shield from a friend and I tried using it this morning while nursing. The first time I tried it it didn't seem to help the pain, but the second time it did seem better. I'm nervous, however, that with the nipple shield she isn't getting enough, so I kept putting her back on the breast when I used it today and feedings took twice as long. It's worth it though, if it can stop the pain - I just know that a lot of people say nipple shields are a huge mistake, so they make me nervous. But at this point, I just really, really want the pain to improve. I also received a pair of Ameda hydrogel pads today that I had ordered after seeing some positive recommendations on the web, so I'm wearing those now to see if they help the nipples to heal a little.
I'll post updates if anything changes. In the meantime, if anyone else out there has further encouragement or advice, please feel free to continue posting!
Thanks again, everyone, for taking the time to reply to my post!