I am in the same boat. I was doing squats. No pop, just a dull ache that set in and gradually worsened. This was my fault as my core wasn’t braced as it should have been.
After a week I visited a Sports Medicine ortho. He examined me, and took x-rays. The diagnosis was an irritated disk. He said it will take about 4 weeks to heal.
At week 3 I started doing light squats to start to rehab my low back. I also built a belt squat machine so I can still go heavy on my legs without loading the spine.
I am getting better but it is taking some time.
Since you have been dealing with the pain for a while, and you haven’t mentioned that you saw an Ortho, I would recommend (internet opinion) seeing one and going the MRI route like Aero51 mentioned.