Nearly 7 yo dd hates pants.
Yes, she's pretty much always been this way.
Maybe her underwear is too tight or itchy/uncomfortable. With the added discomfort of jeans/pants it probably really bothers her. Try a larger size. My DD outgrew her underwear recently and never said anything till they started to bother her. So finally I bought her a larger size and she has not had a problem since. (she only wears them part time since she still wears goodnites) But actually likes them better and thinks they are more comfortable) Hopefully she outgrows that SOON.