Hi AJ
About 1 1/2 years ago, I had several spasms in my lower back which affected my facet joints, the QL (Quadratus Lumborum ) muscles and the psoas muscle. It was so bad that I was getting nauseous and I had to spend my waking hours laying on the floor with my knees bent. I got better but it took a lot of work.
Luckily, I was fortunate enough to see a physiotherapist and an amazing massage therapist who did "active release". The physiotherapist made me work on strengthening my postural muscles and the transversu abdominin muscles of the abs. Ab work, lower back exercises, tons of stretching (at least twice/day) and proprioception work were what I had to work on. I didn't touch a weight. All my work was done using a fitball, a mat and a balance board. Let me tell you, it was no easy feat.
I could give you a list of my exercises, but then you'd have to figure out the form. Instead, probably the closest thing that I have found to my physiotherapy was a book called Pilates on the Ball by Colleen Craig. She also has a video, which combines the fitball with pilates.
www.pilatesontheball.com is the website, but you may be able to find it elsewhere. Don't let the look of the fitball fool you. When I saw the fitball, I thought "what kind of stupid thing is this" and then about 2 minutes later, I looked like a complete imbecile.....
It can be quite challenging. It's also a great tool to help you stretch.
The other thing I found really helpful was taking magnesium. To this day, I also make sure I sleep with a pillow under my knees so as not to compress the facet joints.
I've been doing deadlifts and I haven't had any trouble. No spasms. My psoas muscles get a bit tight from them, but I use my fitball to stretch it out nicely.
I really sympathize with your pain. It's no fun! Hopefully this helps you a little and you find some way to get better.
Wanda