for the past 9 years - since i was 12 or 13 years of age. i am now 21, and it is still there. it begins right at the beginning of the backside of the shaft. it starts off as a bumpy sort of red, but at touch, it feels smooth. it goes down directly to the scrotal
This could be due to acne/imples/ or infection of the hair follicles called folliculitis or some bacterial infection/ fungal infction or some skin nodules etc.
Nothing can be said with surety without having a look at the lesions.
It would be best to reconsult your doctor about your symptoms if they do not resolve and get a proper clinical examination.
Keep the area clean and wear clothes washed in a few drops of chlorhexidine preferably and dried in the sun.
You could take oral antihistamine or antiallergic medications for the itching.