Always check with your Care Provider first. Anything can have adverse effects and anything can become addictive. If you're treating ongoing pain without an apparent cause please talk to someone who can help you identify the cause and treat it instead.
There are actually many natural pain relievers available. And, depending on what's causing the pain, treating the actual ailment will likely relieve the pain without any extra help. For instance, if the pain is due to swelling and the cause of the swelling is treated or the swelling itself is treated, then the pain should dissipate.
However, there are times when a separate pain reliever is needed and the ones I use most often and feel safest with are ....
White Willow Bark - it's very bitter and leaves a bitter aftertaste but can be mixed with honey which really helps. It's essentially aspirin but works much better in tea or liquid form. You can also make a compress and use it on aching joints. It also has anti-inflammatory properties as well making it good for conditions that involve swelling. However, it can cause stomach upset so take with care.
Chamomile - the mildest of pain relievers is often passed up with the thought that because it's so mild it won't work. However, many people find that it helps them greatly simply because it's rarely used for that purpose so no tolerances have built up. It's generally very safe to use and rarely interacts badly with other herbs or medications. It's gentle enough to use for children.
St. Johns Wort - this is also a pain reliever that's often over looked for this purpose. It works well for many people, especially those with nerve pain. It also helps reduce pain by calming the mind and body, a relaxed body will generally hurt less and muscle and joint stress is eased. However, when taking St. Johns you should take care about being in the sun because it causes sun sensitivity.
Birch Bark works well for many people and is fairly safe and easy to use. You can simply peel or pick up some bark, rinse it and boil it for tea. You can sweeten with honey and it mixes well with many other herbs. However, it's also a mild diuretic, so take it with care.
Also, many people find help with Valerian It works in much the same way Marijuana does for pain. Neither are actually pain killers but both work to dull the nerve receptors. They both also relax you and when you're relaxed you hurt less. However, in most states Marijuana is illegal so if you can find a legal alternative, please do. It's not worth breaking the law if something else can be found to work.
Anything can become addictive but belong relived of pain in itself is addictive making the source more likely to be depended upon and abused. If you're unable to afford health care and don't have anyone you can talk to try contacting a Pharmacist or local Midwife, they may be able to help or direct you to someone who can.
I am not a doctor in any way, shape or form.
Please consult your Care Provider before using any herbs or natural medicinals. Anyone can be allergic to anything, if you're unsure it's better not to use it. Double check everything with you Care Provider if you're pregnant or nursing.
Nothing works for everyone and nothing works exactly the same for everyone. Do the research yourself. Don't take any one persons word for anything, no matter how knowledgeable they seem. Doctors with years of experience make mistakes that cost lives. It's your body, (your home, your car, garden, etc etc etc) take responsibility for it.