Lately ive been dealing with bad stomach aches, caused i believe from my acid reflux. However the last few days I have been experiencing a strong pain in my lower back. What could be causing this? After I used the bathroom today it really flared up. I know i didnt hurt it lifting weights or anything, but usually im used to stomach and chest pain, but never back pain. I'd appreciate the help as if this continues, I might need to get it checked out.