Low Back/SI Joint? Please see pictures!

[Nihsnek]

I've been dealing with a nagging injury for a year now. My left part of my low back/upper glute (the spot is RIGHT below the pointy bone) gets really sore and causes a sharp pain after squatting/deadlifting/leg pressing. Nothing seems to instantly resolve it and it does lessen after a few days.

I've focusing on strengthening my core and glutes, but this isn't going away. It feels like it needs to "pop" and only hurts when I try to stick my butt out/arch my low back.

Has anyone experienced this injury? Please see the pictures referencing the exact location. When I feel the area with my hands, I can feel a tendon/muscle move back and forth as well.

PICS NSFW:
Imgur
Imgur

 

[jswain34]

This just happened to me.

1: go to a chiro. Got an immediate reduction in pain severity after my first adjustment.
2. Stop leg pressing. If you have low back issues you shouldnt do leg press. Think about it, your lumbar spine is jammed between whatever weight is bearing down on it through your legs and the pad behind you. You can google it for a much better explanation.
2a. You could try single leg leg press. It can help keep the lumbar/si in a more neutral position. Personally, i can't even do this without annoying my lower back.