My son had a sore back for a few months prior to being diagnosed. At the time, he played hockey and would sometimes get injured and had also had a big growth spurt so, after running tests, his ped couldn't say for certain if the pain was being caused by hockey/injuries or because he'd grown so much, so quickly that it was muscles/ligaments/bones trying to catch up with one another (plus the slouching that came from hunching over the computer when playing games for hours! :facepalm
. Regardless of the cause, her suggestion was that he take advil prior to (and, after, if needed) games/practices to minimize inflammation. At the time, he was taking up to 3-8 advils some weeks (depending on schedule and/or pain). In hindsight, I don't know why I didn't think taking so many advils would cause some sort of harm.
I suppose I thought it was 'temporary' and would end when the injury healed.
About 2 months after starting this, he complained of having some diarrhea in December. But, it went away after a few days. By February, still continuing with the advils, he was losing weight, looking pale and soon began to have stomach flu symptoms. Eventually diagnosed with crohns.
At dx, GI couldn't say whether the back pain was caused by related intestinal inflammation (in which case, the crohns started 'before' the back pain) or if the use of the advils for injury related back pain triggered (not 'caused') the crohns.
But, if possible, I would avoid any nsaids (ibuprofen, advils, etc.)