Hello and welcome to HCM.
As an
Urologist,i assure you, the head and shaft of penis, are all sensitive.
Individually,the sensation may be felt differently,over shaft and head of penis,but all react uniformly in an erection.
A torn
frenulum,healed before 10 years, isn't related to present erections.
The texture over head of penis and shaft of penis are different, in erections.
The color also varies in erections, as the head appears more pinkish, due to the blood supply inside it. If you want my expert opinion,for any doubt,you may send me a direct question. Dr.Matthew J. Mangat.