So is this an oversupply problem, or an undersupply problem despite the
apparent symptoms of oversupply? And how to make it better, so I don't
want to scream when DS gets latched on? He seems to latch on correctly

Neither, as others have said; everything you describe is perfectly normal.

The pain you are struggling with could be (1) just your breasts adjusting to
this new demand, in which case it will get better within a few weeks; (2) an
indication of some subtle problem with your baby's latch, in which case you
need to do some research, possibly with the help of a good lactation
consultant, to figure out what the problem is and fix it, at which point the
pain will get better; or (3) an indication that your nipples are a bit flatter
than is ideal, or some other issue that is kind of a combination of (1) and
(2).

I suspect you're dealing with (1), which is good news; it'll go away by itself
and relatively soon. :-) But I mention the other possibilities in case I can
save you some of what I went through.

I had the flat nipple thing. Although DS seemed to latch on fine (after the
first week or so) and gained weight easily, I had serious pain -- and not just
during feedings, but between them as well -- because, basically, the skin of my
nipples was being stretched out rather too quickly, which ultimately caused the
skin to crack and tear, and once the crack was there (with the nipples still
being subjected to the stretching, frequently and for long periods of time) it
was very difficult to heal.

Eventually I did heal. Meanwhile, I dealt with the pain by taking ibuprofen
and using hydrogel discs on my nipples. The discs (then called Maternimates,
now known as Ameda ComfortGel and available from various vendors of
breastfeeding-related products; there is also a similar product called Soothies
that's available in drugstores) worked MUCH better for me than Lansinoh. I
recommend trying them; they'll help even if what you're experiencing is "just"
normal initial-six-weeks-getting-used-to-it soreness.

Congrats on the birth of your son, and welcome to the group!
Holly
Mom to Camden, 3yo
EDD #2 6/8/04