Over the weekend I was working on my 96 Max, replacing the power steering pump. I had the car raised on the right side pretty much all day Saturday through Sunday. When I finally got the pump mounted and the belt back on I used a second jack to raise the left side so I could turn the wheels back n forth to break in the new pump. After that was all done, I lowered the car back down and took it for a test drive. I immediately noticed from going over the speedbumps in my neighborhood that the left front suspension (stock) had become VERRRRRRRY stiff. Now when my left side hits any sort of bump, dip, pothole... any little imperfection in the road... it's just SOOOO freakin harsh. It's like being a bobblehead but actually way worse :P It wasn't even close to being like this before I raised the car. Like night and day. I can even feel the stiffness when I push down on the left front side of the car. The other 3 locations get normal up/down bouncy motion but the left front resists a LOT when I try to push down. Any thoughts on why/how this could've happened all of a sudden, and any ideas on how to solve it?

Your left strut has failed. Replace it. You should really at least replace the front 2 struts together.

Sounds similar to an issue I had with my Maxima recently. The strut mount may have failed. The mount is basically rubber mounted in a metal casing. The rubber may have torn away from the metal. I was getting a squeaking noise but also noticed that I was getting a jarring noise over bumps. Take a look under the hood inside the strut mount/strut assembly while you are jacking the car up. You can compare what is happening with the other side. If the mount is bad the strut bolt will drop quite a bit compared to the good side.