I am 36 years old and I am getting constant pain on my penis. Especially when I masturbate. When I have sex with my wife it does not pain me. But whenever I masturbate my penis pain like anything that I can not bear it. I visited a doctor who said there is nothing to worry at the start. Later when the pain didn't stop I visited again as I had body pain as well. After blood test it was seen that my vitamin b12 and d3 was lower than minimum. I am under medication for the same. But still I get constant pain ok n my penis. It is especially on the head of my penis. Is there anything wrong? I even visited a neurologist who said there is nothing to worry. But I am really worried as because of the pain I am unable to have sexual relation with my wife.