I also like the Scotch, though, most the people I play against don't like to take the full exchange of pawns and knights.
From here as Black, I don't like using ...c5 to chase the queen because it doesn't do much more than weaken your position and block in the bishop. It's probably best to just develop normally with ...Ne7.
I love the Scotch as well. I do not enjoy closed position games, so this game provides more tactical and exciting play. Pandonfini's book "the ultimate chess guide" (which is an incredible book) uses the Scotch to teach chess. This is the same teacher who is in the movie "Searching for Bobby Fischer."
As far as the next move, I would go back to developing as wolfstriker has suggested. We want to avoid wasting too many moves and using the queen to early. (remember the movie where Pandonfini said this? ...he also says the same in this wonderful book for beginners).
Scotch opening, full trading by both players. After this, white queen is found to be open in the middle of the board, being the only player having 2 pieces out there in the center to black's 0.
What are black's best moves? 1 or 2 variations will suffice.
I absolutly love this opening when I play white, and I enjoy as black too. Normally, I would do c5.
PS: Should be written : Black's turn to move