Oddly enough I am at the same point you describe. Psa of 1 never above 2. Diagnosed with enlarged prostate in 2016.
had issues with back pain ,given a ct as with a Pacemaker an mri is more complicated.
diagbosed with spine degeneration at all levels. I am 65 told normal at my age. Happy with that, however recent suffered excruciating hip and leg pain one night which was so bad I assumed it was nerve related. These symptoms have subsided but back ache now in centre and too if back, so back on the Pca worry.
have had an mri of lumbar spine awaiting results but very worried and am have been seeking anyone else who may have been diagnosed with spine mets but normal psa.
sounds like yours turned out to be ok.
al