Well, you guys are the best!! I knew someone here would know what to do.
I took off the top, oiled everything connected to the needle position lever and got it moving freely. The needle bar itself still didn't move, so I opened that side door, oiled everything there I could find, and then finally, I confess, I pushed the bar with my thumb as I moved the needle position lever. hehehe That broke the seal of whatever was holding it rigid, and now it's moving fine.
All the cams are working great now. Zig zag back on track too.
Many thanks to both of you for the suggestions! And for saving me $100!
(I bookmarked those links for the future, too.)