Honestly, it depends. It can hurt/be sore at first, but not always. It's definitely usual for there to be some soreness while your nipples get used to it (both in terms of toughening up and how to allow/guide baby to latch properly/effectively) and baby is learning too. If it's really painful, then you should ask for assistance as it's highly likely that there is something that needs correcting (could be a simple latch issue, could be tongue tie). The soreness doesn't usually last too long (if it did, nobody would breastfeed for months/years!).
DC 1 - significant tongue tie, breastfeeding was very painful at first and complicated by initial latches being terrible (because I didn't know what I was doing and latch wasn't checked by midwife early enough) and causing a lot of damage (I still have scars and misshapen nipples today!), but we persevered. His tongue tie had to be cut twice (once at 5 days, once at 6 weeks), which didn't help... the toe curling pain did last for weeks and in hindsight, I probably shouldn't have put myself through what I did (it was traumatic physically and mentally, but I was determined to breastfeed and didn't want to "fail" 🤦♀️), however breastfeeding was eventually established and pain free. I breastfed him until he was 2.5. I've included this experience because although it does sound awful, it is real and it would be unfair not to say that this can happen, but please bear in mind that my experience with DC 1 isn't typical for the majority of women (and the extent of the pain could have been avoided with better initial breastfeeding support). I 100% back the "it shouldn't hurt if you're doing it correctly" approach, because toe curling pain when breastfeeding isn't normal (soreness certainly can be... but soreness and pain are very different).
DC 2 - mild tongue tie (never cut)... the latch was a little sore but completely manageable for a few days while my nipples were getting used to being used again, then it felt completely normal, no soreness at all about a week in. My experience was completely different (and the experience of being able to breastfeed so easily without issues was actually quite healing). I breastfed him for 2 years.
DC 3 - significant tongue tie which was picked up by me (when she was screaming and still in the birth pool 🤣) before I even latched her on for the first time. This meant I was super careful when latching her on, but it was still quite nippy and sore compared to DC2 (better than DC1, though, because I knew how to avoid a damaging latch). Her tongue tie was cut about 5 days in and the latch (and therefore soreness) was immediately much better. I got away with very mild friction sores which healed very quickly (never blistered, unlike with DC1!) and it was only ever sore, not painful (goes to show how avoidable my experience with DC 1 was). The soreness was fully gone by about 2 weeks in and I'm still breastfeeding a year in.
Lansinoh (or any lanolin cream) is great as it eases friction when feeding and therefore reduces soreness... it also aids healing if you have any sore areas on your nipples. I highly recommend attending an antenatal breastfeeding class and then going to breastfeeding groups/clinics afterwards if you're at all unsure of anything.