Well, this could certainly be an issue with nerve irritation, as nerve irritation can cause the muscles in the lower back to spasm and cause pain.
This would also make sense in the fact that when you are stressing and using the lower back muscles (changing positions, bending, etc) -- that this makes the pain worse.
However, to obtain anything stronger than Advil or Aleve - you would have to be seen by a medical professional. This, in your case, would mean being seen in an urgent care center, or by your primary care doctor.
You will not be able to get any type of medication prescribed in any other way. It is against the law to do anything online.
What can I do to relieve pain caused by a pinched nerve? Should I stretch, put ice on it, heat, what? Like I said, I don't recall doing anything to cause this, it just came on suddenly. Will it go away on its own? What can I do to make it go away or ease the pain? Would you recommend a chiropractic visit? what would you recommend that I do?
I would try heat before ice, but certainly which ever one works for you would be fine.
In general, this type of pain does improve with time, generally several days to a few weeks, as nerve inflammation improves with time. Continuing to take the medications, the ibuprofen or naproxen can help eventually, because they also are anti-inflammatory pain relievers, and can help with the inflammation in the nerve.
I would not recommend a chiropractic visit.
If you need something stronger for pain during this time, unfortunately, a visit to urgent care is all I can recommend, as you would need to see a physician to get stronger medications prescribed.