Basically, pain medications are prescribed drugs (under the guidance of an expert licensed professional) i.e. used to relieve discomfort associated with disease, injury, or surgery, etc. as the pain process is a bit complex, there are several types and drug classifications of pain relieving drugs that provide relief by acting through a variety of physiological tactics. Thus, effective medication for nerve pain will likely have a different mechanism of action than arthritis pain medication.

Let's understand it by an example; Suppose you're having a mild headache or muscle pain or neck pain or similar problem, in this case only an over-the-counter pain reliever (also known as OTC medication) is usually enough to make you feel better during surviving the severe pain. But if your pain gets more severe, then there is a strong recommendation for your pain healing i.e. a prescription opioid.

Oxycodone (Oxycontin):

Generally, Oxycontin is used to help alleviate severe ongoing pain. It works in the brain to change how our body feels and reacts to the pain. The higher strengths of Oxycontin or Oxycodone (more than 40 milligrams per tablet) should be used only if you have been regularly taking moderate to large amounts of opioid pain medication. These strengths may cause overdose (even death) if taken by a person who has not been regularly taking opioids. Remember Do not use the extended-release form of Oxycontin to relieve pain that is mild or that is gonna last just for a few days.
Take this medication on a regular schedule as directed by your doctor, not as needed for sudden (breakthrough) pain. Take this drug with or without food, usually every 12 hours. If you have nausea, it may help to take this drug with food.

Hydrocodone-Acetaminophen:

Similar to Oxycodone, Hydrocodone-Acetaminophen is also used to fix severe & ongoing pain. Containing an opioid pain reliever (hydrocodone) and a non-opioid pain reliever (acetaminophen) Hydrocodone-Acetaminophen is used to relieve moderate to severe pain. In case if you are using a liquid form of this medication, use a medication measuring device to carefully measure the prescribed dose. Do not use a household spoon because you may not get the correct dose.