If I had to guess, I would say yesterday was more a distribution day more so than shorts starting new positions. Any shorts that did start positions were probably squeezed out on yesterday afternoons move.
The problem then is, that a 10 point gap up today doesn't leave room for a short squeeze, while longs are afraid to enter as we are near all time highs. Historically, the 3rd, but rather 4th test near a high (on a daily chart)produces a strong breakout near the open.
So where are we right now ? Lots of uncertainty. People unwilling to pull the trigger, and no fear or greed. Minimal opportunity.......choose your positions wisely. Don't give up yesterday's profits trying to eek out a point or two in this crap! Staying flat is sometimes your best friend.