Years ago my pain specialist put in a prescription for a pain cream to be formulated by a local compounding store. It was a small jar of a white cream. I applied it to my back and butt, where the majority of my pain was. I think it cost about $50 since it wasn't covered by insurance. If it did anything, I couldn't notice it. I saw that the key ingredient was lidocaine, 2%.
A while later I bought a 4 oz. bottle of Aspercreme for about $16, 4% lidocaine. I could actually feel a little pain mitigation from it. Don't always assume that a costly Rx will work better than an OTC product, especially tking into account the cost.