Yes, and yes. The reason you weren't taught much theory is because on a horn you're only playing one note. But I think that's really a shame, because you were deprived of the understand of what you were playing and why, in the context of the notes and chords that the rest of the band was playing. And even when playing a horn solo piece, there is always an understandable, chord-based structure to the piece.

Edit: Also it really doesn't take much effort or theory to understand most of what would be interesting. Like many subjects, the 80% of what's helpful can be written on just a few pages and learned in a few hours - but whole college curriculums can be made of the details and nuances. Go read up on 7th chords, cadences, and simple chord progressions if interested.