I am a 90 % ear player and I do ok. Some stuff is just to fast or the note expressions are too intense for me (Hoffmann is good at that shit >: ) to figure out exactly, but I can usually come close. "Pitch" is learned to a great degree, but it is also something you seem to be born with or at least something you learn at a young age probably involuntarily (if you liked music as a child which I did.)
I am referring to "relative pitch." Some people have perfect pitch according to popular belief, but I don't. Perfect pitch is just as it sounds. If you play a note on an instrument, that person could repeat it in his/her mind.
To start playing by ear, playing either acoustic (oldschool country/folk) or playing 80's hair metal is the way to go. The oldschool country acoustic stuff uses a lot of open chords, and if you know say just 10 of the most basic common chords, you can play thousands of those songs. Try to "match" the chords you know with what they are playing.
Many "hair-metal" bands use your basic "power chords" which are barre chords using two or three strings. Not all bands do. Ratt was interesting rythmically on some of their stuff for example, so was White Lion, so stay away from them. Anyway, you will learn to "match" those chords as well if you try.
Once you can play rythms by ear, you graduate to more complicated riffs and solos. One of the coolest things about learning to play by ear is that you do make mistakes. Sometimes YOUR version of the song sounds better than theirs. When I make mistakes, I most often realize them later and change them, but on several songs, I still play it my way.
I realize I may be talking down to you as you are probably already somewhat advanced as a player or you wouldn't be here in this particular forum, but I know guys that can play Yngwie solos from tab, but couldn't pick out a Motley Crue chord progression by ear. I am not saying that is you, but I am simply telling you how I did my ear training. I started with early Dio and hair metal bands chord progressions.
Bryant