Sore nipples can heal rapidly in a day or two but you are using them alot so it is easier to prevent them than to treat them. During last months of pregancy - incorporate in intimacy - get those babies used to being used! Post-partnum - if they are constantly sore or suddenly sore - may suspect thrush (other symptoms are pink, flaky skin and itchy nipples  (Thrush is due to candida albicans and is the primary suspet if baby seems hungry but fusses instead of nursing - look inside mouth of baby. Are insides redder than normal? are there patches of white? - Check out Susan S. Weed's book mentioned in previous post for remedies to get rid of those pesky yeast).
For preventing sore nipples; expose breast to air, don't wear a bra all day/night. Wear nursing bra with flaps down as much as possible. Expose breast to sunlight or brief periods of ultraviolet light (max. 3 min.), rub olive oil, sweet almond oil, lanolin, comfrey root ointment into nipples throughout latter part of pregnancy and beginning weeks of nursing. Make sure baby is placed correctly and nipple is centered. Experiment with different nursing positions. Avoid washing nipples with soap which removes natural oils.
Remedies: crshed ice in wet cloth before nursing. Use comfrey root ointment (softens and strengthens nipples). Rinse off before nursing so baby can grasp properly. I have made comfrey and calendula ointments (take some dried herbs and good olive oil - heat on low 4 hours. I add a little bee's wax then pour into jars - great for cuts, scrapes, nipples, skin rashes, eczema, etc). Also good are yarrow leaf in poutices aor oinments to totaly reliev apin and heal rapidly. Vitamin E after nursing. Any poutlices for painful breast are good esp. comfrey and marshmallow. Clear gel from an aloe vera leaf (wash off, can taste bitter for baby). Avoid antibiotic ointment, steroids, and anesthetic drugs which are potentially harmful to you and baby.