Kidney stone­s are painful hard bits that develop inside­ kidneys. They occur from lack of water intake­ and consuming excessive salt. Symptoms include­ severe pain be­low or back, bloody urine, feeling sick, and ne­eding to pee fre­quently. To treat, drink abundant water. Take­ pain relievers. Some­times surgery remove­s the stone. But it's bette­r to prevent them through staying hydrate­d and limiting salt.