Try to avoid clothing that sits directly over your c-section scar. This can mean choosing different underwear or even pants. Consider doing this for a few months, as the tissue heals, you can try introducing your old wardrobe back in and may not have a problem with it.
Be sure to keep your c-section incision site clean and dry. If you are having trouble keeping the area dry due to the shelf of skin that can sometimes hang over the incision, ask your doctor about using something like corn starch once the site is completely healed. You can also use gauze or cotton to tuck into the shelf. Be sure to thoroughly dry the skin after bathing.