Toe-curling initial latching in the early days is not uncommon and may link to the issue of sensitivity discussed earlier. A slow count of ten and some deep breaths should be sufficient for it to pass, otherwise it's likely to be caused by something beyond breast tissue stretching and the nipple making its way to the back of the baby's mouth... If it does not ease in that length of time, then that is worth a closer look by someone skilled in breastfeeding at positioning and attachment (latch).
Usually the stage of feeling this discomfort passes fairly quickly, although in addition many women do report sensations ranging from tingling, to prickling to stabbing pains as their milk starts to flow more readily during a feed (let-down). The sensation is short-lived during each feed, but how many weeks/months it may be experienced by the mother seems very variable. Whether or not any sensation is felt seems to have no bearing on successful breastfeeing.
I can only re-iterate, that I have observed many mothers with babies sometimes only a few days old being helped by experienced volunteers with positioning and attachment. Babies may have small mouths and sometimes in combination with a mother with large nipples. In many cases small adjustments do lead to a noticable improvement for the mother, even when others have told her repeatedly that her baby's latch is fine or even 'perfect'.
There is also an element of re-learning with each baby, as when we've fed a previous baby, or most recent memories are of feeding a bigger baby. A newborn is a different thing, and each mother/baby pair are unique and fit together in their own way. Feeding each child can be a different experience.
To give you a personal example, I've already said I had nipple trauma and pain with ds that was eventually improved when he was aroung 3-4 weeks old with skilled help from a bf Supporter. Many many MWs and one HV had all told me things looked really good, but it hurt a lot . Basically, I continued searching for alternative sources of supprt until I found someone able to help me. With dd, I never experienced nipple trauma at all and all I had was a few days of sensitivity, which as I've said was just like that I'd had throughout pregnancy. We had qualified bf help from when she was 6hrs old, and yes another person was able to make helpful suggestions to keep us on track as we learned together.