What's the best over-the-counter pain reliever for severe pain such as back pain from pinched nerves?

Ibuprofen

I dont know where you are on the globe , but if you are able to try this.

It says headaches, but works on a multitude of aches.

Im not sure if its because its soluble, but it seems to hit the nerve endings almost instantly.

& the pains seems to disappear for a long while

Tequila.

Cannabis

Rum

Alternating every 2 hours.

Paracetamol

Ibuprofen

Consider Co-Codamol also

co-codamol, they help my pain a great deal.

Voltarol to rub on your back & ibuprofen.

800mg of ibuprofen

Ibuprofen

Excedrin. It's ibuprofen, caffeine and codeine. Closest you're gonna get short of morphene.