Tweetwell you tend to carry more fat on the ass, unlike your delts and quads, so your glutes absorb it better...as far as the delts and quads, did you use the same needle length/size? if so, did you penetrate all the way in...seems like both of those muscles were not ready for it and they will get use to it the more frequent you do it....sorry for the pain man, but don't be a *****
hope you get better
and why ED and not EOD for the tren?