I think it really depends on the kid... my besties son has always been very easy that way. Even at a super young age you could give him a deck of cards and his little mind would go crazy and he's play alone in his room for hours if you let him. LOL. My step-daughter has NEVER been this way... only in the past few years (she's now 14) will she make the choice to go read alone in her room or listen to music etc... otherwise, she wants to be around people ALL the time. She even has a hard time being quiet- but again, much better now that she's older. With her though, it stemmed from her anxiety- and feeling better around people. It was really hard when she was little though- cause she wanted to be around us or have friends over... and for us, it was easier to let her have a friend over at times to play so we didn't have to "entertain" her 24/7. Ok, maybe not 24/7-- but it felt like it!!! She is just a very social and energetic child.
Some kids are just WAY more social than others... they like being around people. Of course I would recommend encouraging him to do things on his own as well- but that can certainly be frustrating at times. I know. But as he matures, most likely he'll find there are times he likes having his "alone" time as well.
Maybe find some time during the day he can read or play with friends or be creative? Something to keep him busy so you have some time and he can expand his activities? Just my two cents. All very normal though.
