Sounds like he's a social kid with a lot of energy. How often does he go out to see other kids? How often does he get outside? My almost-three year old does play with toys, but he's honestly happier 'bouncing around' or outdoors. Kids are unique, and some tend more towards imaginative play with toys, while some tend towards social play.
Overall, it sounds like your particular child needs more social attention, whether it's from you or from others. Get him into playgroups, have friends over, etc, when you can.
During times when he's required to be alone in the house, like when you need to cook/clean/whatever, consider getting him to do activities that he can do with you. If you're loading the dishwasher, he can probably help - my oldest has been loading the dishwasher since he was 2 (with all glass/porcelain dishes). If you're cooking, he can help mix the dough or sauce.
If you're doing something he can't participate in, consider activities that allow him to be near you and allow you to talk to him. Maybe he can do play-doh or color at the kitchen table; you can talk to him while you work about what he's doing. You may have to work with him more directly at first - get him to think of the activity as a social activity. By four, he probably can "read" books to you, at least ones that he's memorized; ask him to do that out loud.