Bless your heart. I can certainly understand the pain. I've been in chronic severe pain for over 27 years now, and it's been miserable.
As for OTC medications that won't mess with your liver -- that's kind of hard. So many of them are terrible on the liver, and others might make you bleed to death if you take too many!

You're darned if you do and darned if you don't.
I know for me, I've always gotten the best relief from aspirin -- it doesn't help my severe pain -- but it DOES help stuff like headaches. And I DO get horrible headaches from a herniation in my neck. If I take 2 aspirin, it USUALLY helps that -- but it won't TOUCH the lumbar spine. That's where the majority of my problems are.
I am being treated though, so I'm lucky there. The meds keep me "somewhat" semi-comfortable, although today is a terrible day. I also have Fibro, along with a list of other delightful things.
I wish I knew what to tell you. Any OTC things that would really HELP you, would have to be taken by the handful to do any good -- and they'd be too dangerous!!! They'd eat your stomach, cause you to bleed, or damage your liver! So take your pick. Tylenol (liver) Advil (stomach) Ibuprofen (stomach) Aspirin (bleeding) Naproxen (stomach/liver too I think

)
Aren't they all delightful? Wish I could come up with something better.
Best of luck and God bless! Hugs, Lee