A little background.
M/33/225
Work Sets after about a year of strength focus (after a 1.5 years of metcon style workouts)
Sq 345-365lbs
DL 315-325lbs
SP 165-175lbs
BP 245-255lbs
PC 175-180lbs

I laid off of working out for about a week because of a vasectomy. Returned with squatting 335 lbs and power cleaning 165 lbs for sets. Woke up the next day a bit sorer than usual. After a day of rest I squatted 315lbs for sets and realized I should have taken another day for recovery. The day after I had a localized pain on the left side of my lower back (1-1.5in below my belt line).

The pain I'm having in the lower back fires up when I do knee raise type movements with the left leg (getting in bed, in a car, on a flat bench for presses, etc.) It's been two weeks and the pain has not subsided. I've begun spinal decompression therapy for the past week after using the search function for lower back pain. However, I haven't felt much progress.

Is this the type of pain common for disc herniation? Could the pain be associated with a different type of back injury?

It doesn't cause any additional pain when I squat without weights, or when I do deadlift type movements. It only fires when the left leg is in a canilever type position.

Steve.