Nightmares in children?

I have seven children and two out of them all experience bad night terrors. Im thinking it may be heredity,because my husband remembers have them as well. My older son actually grew out of them,but now talks alot in his sleep. My daughter is 4 and has had them for two years now,but it getting to the point where she is doing them 20 times a night. She will get into a good sleep then all of a sudden Scream and cry. We then call her by her name and try to wake her,then she will reply WHAT! Like nothings happening. She will then fall back to sleep 15 mins later and repeat the whole thing over again. Sometimes she will say her head hurts and thats whats worring me..It's pretty scary,and mind boggling to us..Ive done alot of research and from what Ive been told and read it is normal..But to me this is not just your "normal" nightmare..her Dr gave her something to help her sleep,but I dont like giving a 4 year old meds every night to sleep,and the meds only make them worse! Any information on experience or know how would greatly help...Thank you!