Trauma to lower backresulting in multiple lumps just above the si jointover the erector spinae group and lumbarcausing me to lean forward?

Back spasm: The lumps may be the bony prominences in this area or can be a muscle spasm. If your pain is persistent and radiates down a leg, imaging may be needed to help with diagnosis. The leaning forward is a way of decompressing the spinal canal. This may take pressure off a nerve root. If leaning back exacerbates pain, i recommend seeing your doctor and possible imaging.