Natural Pain Killers

Gunja.

opium has to be the best natural pain killer around. higly addictive, so you might want to take that into consideration.

W-18.

for long term pain relief to help rid yourself of tramadol and all that other shit, try 6 stiff joints a day, promise you it along with a lot smaller dose of opiate based relief , it works a treat from personal exp
contact me if you need more info-cheers

What kind of pain?

Depends on the severity and type of pain.
From opium tea and tincture, cannabis oils and tinctures ... note not all cannabis is created equal for this purpose ... through to wild lettuce (Lactuca virosa) which grows in most home back yards. Wild lettuce has a similar effect to mild opium without the side effects.
Kava is a great muscle relaxant and stress reliever too, but you need to go to fiji, etc, or know someone who is ... 2kg limit per person back into the country as kava cannot be imported via other means. Or get to know someone in an islander community, they'll sort you out.

These days I use the Magical Butter machine to make home medicines in oil or grain alcohol based product. Tinctures can take four to six months if done properly although can be done in two.
Cannabis tinctures can be made to be psychoactive or not using grain alcohol, food grade glycerine or honey or a combination thereof.

https://en.m.wikipedia.org/wiki/Mitragyna_speciosa
Kratom is a plant substance