THR Lower back pain

Hi everyone. I'm 4 days post-op and I'm really struggling with lower back pain. Is this normal? I woke up in the recovery room pain with excruciating pain in my lower back. When they moved me to a normal hospital bed it was manageable but since I've been home it's not really getting any better. My bed is quite a soft one, and I'm wondering if that could be part of the problem. Getting up and walking a little does relieve it but that's not something I should be doing too much of yet.