You met an RTA while you were in car 8 years back and had disc injury
and you gradually developed pain at your back and erection of your penis occasionally . It seems your disc bulge(if no operative removal done) or other spinal pathology causing compression of spinal nerve
It can be diagnosed by proper examination and investigation including MRI n x ray which will revel bony or soft tissue
involvement ,level, cause..... Now if no gross bony abnormalities present then you need to do regular physiotherapy
, warm compression , avoiding sternous activity / bending forward , vitamins (B 12 folate ...), analgesic (NSAID) PPI , Muscle relaxant
n LS belt application.
If gross bony abnormalities present then may require operative decompression n fixation .
So in my opinion visit orthopaedic clinic if symptom aggravates or does not relieve even after 2weeks of conservative management .
Hope this ll help
Thanks n regards