Capoor, Manu N., et al. Propionibacterium acnes biofilm is present in intervertebral discs of patients undergoing microdiscectomy. PloS one 12.4 (2017): e0174518.
https://dx.doi.org/10.1371%2Fjournal.pone.0174518
Birkenmaier, Christof. Should we start treating chronic low back pain with antibiotics rather than with pain medications?. The Korean journal of pain 26.4 (2013): 327-335.
https://dx.doi.org/10.3344%2Fkjp.2013.26.4.327
>The results of this research indicate, that chronic low back pain associated with bone marrow edema in vertebral endplates that are adjacent to herniated intervertebral discs may be caused by infections with anaerobic bacteria of low virulence. According to these articles, treatment with certain antibiotics is significantly more effective than placebo against this low back pain. If these findings are to hold true in repeat studies by other researchers, they stand to fundamentally change our concepts of low back pain, degenerative disc disease and in consequence the suitable therapies for these entities.
A round of tetracycline or similiar antibiotics might be an interesting experiment. Anything else you can tell us about the situation of your back? I know you say it happened while squatting, so it would seem to point to the problem being from the mechanical injury to the spine, but what if mechanical injury allows an opportunistic infection that prolongs back pain? Do you have an acne?