Greetings mesor, I will be your instructor for today.
Wipe that confused expression of your face. This will be brief enough for your attention span.
The Nervous System, in a nutshell, is basically the only system that is responsible for conscious and unconscious action in your body -- reflexes, movements, voluntary force and what not. Now, you talk about pain receptors as if they were redundant, yes?
There are worse things out there. A normal human basically has no fall-back system to rely on if the nerves are damaged. Worse yet, most nerves (the general ones in the body)
cannot regenerate, and pay for that weakness by having a longer life span than most of your other cells. Yes, cells are what makes up your body, and they die every day.
Now, without those pain receptors, you will be
completely apathetic to all notions of pain. This includes minor bleeding and parasitic infection.
Severing your nervous system completely renders you like a...what's the innocent word...oh right, a dummy. A literal walking meatbag. Not only will you die horribly (but 'painlessly', heh) your organs will cease to function. Everything will fail, and basically, a slow ignoble death. Don't let me get into the basics that your nervous system is divided into two major portions...
Next, painkillers. You know nothing about those things other than 'they kill pain', aye? Yeah.
Nope.
Analgesics (painkillers) act on your nervous system. Remove your nervous system, and that is useless. You can't feel useless though, but I'm verging from my point. Painkillers is a generic term, if you want
every effect to work on you, I'd be happy to tell you that you'll end up dying. Slowly, horribly, and yet like a clown -- too unaware to care, keeping on smiling... (No offense clowns)
Overdosing any type of painkiller will affect your body in 'bad' ways. Organ damage, brain damage, muscular death...let's just say that playing it by
let's test every painkiller until I find something that works is
NOT a smart option.
But what do I care? It's the future. Fuuuuuutuuuuuuure!
Edit: Also, you can practically sever your pain receptors, but that would be a costly (and stupid) thing to do. You won't know if you're infected, sporting parasites -- alien or not, and you won't even know that when I revive, I'm shoving a dagger up your spine.
Technology. Do you know the meaning of it? Do you know what the difference of medicine and technology is?