I use To Have REALLY curly/frizzy hair. & Now , at the end it stays really straight & has no volume at all. When I went to get my hair done one day, I asked why? & they said it can be due to straighting your hair too much or just because some parts of your hair is older than other. Or due to getting perms .
I've had that problem and still do eventhough I get my hair done once a month instead of twice.the ends are straight from previous days but deep conditioning has helped with the hair closer to my scalp.
Its over processing if your hair that's now growing out of your head is curly like if you flat iron/blow dry a lot and don't chemically treat it..also some curlies have straight hair when its wet then as it dries to turns curly