Your history suggests that left side of your penis is more sensitive to touch, pain, pleasure sensations. One thing is you are getting erection so the problem is not so serious. Deviation of the penis to the right or left or upperside is very common in many males. So you need not to worry for that. Regarding sensations there might be some past local skin lesions or white patches or some mild fungal infection which might have reduced your skin sensitivity. My advice is you first visit dermatogist, he will examine you and accordingly prescribe you medicines. Sometimes, as it is related to genitals, there is only psychological perception rather than real medical issue. So dont worry, get yourself examined. Hope this will help you.