I had two different instances of back pain (they were probably over a year apart). First one persisted for a while (ibuprofen didn't make me feel any better) and I had to go to the doctor. He suggested me to take higher dose of ibuprofen for a week. His reason was there might be some inflammation and the lower dose that I was taking was not enough. He also told me that the pain killer will help reduce the inflammation and eventually the pain will go away. He also told me that it will take a couple of months if not more for the pain to completely go away. He was right.

The second back pain went away when I changed my mattress.