need help ASAP please!!

ive been having this problem for quite a while now and i tried to google it to find the answer but couldnt.. i made an account here specifically just so i could get this problem fixed. anyways, when i add a song to my itunes library it has the correct artist and song title, but then when i add it to my iphone it is under a different artist name. i dont know what the problem is or how to fix it, if anyone could help me it would be greatly appreciated.

also, sometimes it wont even put the artist in the "artists" category, ill have to go to the "albums" category to find it

Sounds like the tags are a bit wonky. In iTunes (on your Mac), select the song (single-click) then Get Info (command-i). Take a look at the information and let us know what's there.

Also double check the info on all of your Cd's. Sometimes there are two different sets of info for the same disc.