I Have Been Having Really Bad Back Pains That Have

I have been having really bad back pains that have lasted for almost a month. The pain started as an ache, but has progressed. It now feels like intense pressure in the middle of my back, like if I move a certain way it might pop. I have the same issue with a knee, but typically after I pop my knee, the pressure and pain go away. I am afraid to pop my back, especially since the pain has been so bad recently that even the backs of my legs start to cramp while standing. I have also noticed an onset of diarrhea that has lasted for the last 2 days or so. I have been using heat packs and ibuprofen, but nothing as helped and no position is comfortable, even laying flat. I haven't been able to sleep for a few days because every movement wakes me up.