My boy eight years old a lil over weight but not obese. His penis is the same size as when he was born. It also dosnt get hard at all. Do I need to worry?

Hard to say. Overweight kids often position some of their fat stores in the tissues surrounding the penis and scrotum. That fat padding can cause the penis to appear small. Intermittent erections do occur in kids but the lack of noticed events is no cause for concern at this age. Mention your concern at his next checkup. If needed the doc can do some testing, but most are normal.