Don't judge me :(
Is 'you are wearing big trousers' also correct?
Nope. See here: https://forum.duolingo.com/comment/27628688
why would you say that to anyone or why would you even wear trousers that are to big
Are trousers and pants technically the same word in this, or is there a different word for pants? (I rarely use the word trousers in day to day speech, haha)
Well, it depends what you mean by "pants", but if you rarely use the word "trousers" then I guess you speak American English?
"pants" as in "underwear" are "majtki".
"pants" as the thing that you rather wear on your underwear ;) are "spodnie".