This is Dr. DavidI am another expert here at this site. I have another opinion. I don't think the damage of the nerves is from the spine. the dorsal penile nerve runs along the top of the penis and controls sensation to the penis. http://www.hawaii.edu/hivandaids/Innervation_of_the_Human_Glans_Penis.pdfif you had spine impingement, this would also affect erections, but you are able to have erections.
I suspect that from your frequent prior masturbation and sexual activity, you have traumatized your dorsal penile nerve.I would recommend that you take a break from masturbation and sex and allow your dorsal penile nerve to rest. and see a neurologist and get magnesium blood testing to check your magnesium levels
low magnesium levels can affect nerve function as well.
also when you have sex or masturbate, make sure you don't put extra pressure on the dorsal nerve and dorsal vein which run at the very top of your penis.