I’ve found a number of them. Labs typically have at least one autodoc (with 3 anesthetic outside the door to the autodoc chamber), sometimes more. Hospitals have autodocs as well. I’ve found anesthetic in both veterinarian clinics and doctors offices.
There is also a version of the military bunker which has an autodoc inside it, though I’m unsure if it is part of the base game or from one of the locations mods that are packaged with it. I actually built my home base inside one of them specifically because it had an autodoc. That way I wouldn’t have to go on a road trip every time I wanted to install a CBM into one of my followers.
I don’t think it would be even remotely practical for someone doped up on painkillers to perform intricate surgery on themselves like would be necessary to install any kind of cybernetic part.
Even if you couldn’t feel pain, and as a result performed the surgery on yourself clearheaded, it would still be nigh impossible to operate on any portion of your own body that isn’t easily visible and accessible. You wouldn’t be able to do it one handed either. This means no self-installed brain or head implants, no arm or finger augmentations, no augmentations of the digestive system or internal organs.
Assuming you can operate on yourself without being stoned on painkillers or overcome by agony, you might practically be able to install something like say, subdermal armor plating in your own legs or the front of your chest. I wouldn’t want to try it though.
Now operating on someone ELSE is a different story entirely. All you would need then is skill.