I was prescribed a wonderful drug for arthritic pain in my neck, back and feet. The drug was Indocin (indomethacin.) It's an NSAID - that means "non-steroidal anti-inflammatory drug." That puts it in the same family as aspirin and ibuprofen. Indocin is by prescription only, and it's way, way, way stronger than ibuprofen. It's great! I had been taking Vicodin, an opioid, but Indocin was way better. It made me feel 10 years younger.
Unfortunately there was a price to pay. It works by stopping the body from producing prostaglandins. That gets rid of inflammation with beautiful results. (They even use it for gout, which is terribly painful.) However, prostaglandins are what keep the lining of your whole digestive tract protected by a layer of mucus. Stop the prostaglandin production and that protective mucus starts to thin out. In my case, I developed bleeding ulcers in my stomach and colon. Gradually, I lost so much blood that I was near collapsing. I ended up in the hospital needing blood transfusions.
So no doctor will order Indocin for me again, which I agree with. I'm back to making do with the Vicodin. I've been told not to take even an aspirin or a Motrin. Opioids are actually less damaging than NSAIDS, as long as you don't take enough to slow down your breathing. I would say opioids are less toxic than Tylenol, which can be bad for your liver. So I rely on this opioid drug, Vicodin.
Any drug powerful enough to do you a lot of good is going to come with the potential to harm you. That's the catch. Don't think Big Pharma isn't doing all kind of research to try and come up with a new class of pain killer. It's not easy. All drugs come with potential bad side effects. Plain water can be toxic, if you drink enough of it, as Brooke Shields found out.
I think they've gone way overboard in restricting opioids to people in pain. People think NSAIDs and Tylenol are safer because many of them are over-the-counter. That's leading to trouble, since these drugs are not all that safe.
Of course, opioids get less effective over time, as you develop tolerance. By now, you probably know about that first-hand.
TENS units got real popular in the '70s. Hospitals were really into using them. They seemed to have little downside. Then, in the '80s, I stopped seeing them in hospitals. They fell out of favor. My guess is that they weren't all that great at relieving pain. I find warm baths and warm showers help my pain a lot. A cold pack on my neck helps. I like these warm packs that you can heat up in the microwave. (I think they are full of seeds of some kind.) Good luck with your efforts to manage your pain.