Many children get bored when they have no other kids or adults to play with. It's just normal. You probably have recollections of, when you were younger, those rainy days that seemed endless, or those family visits where it was all about long dialogues between grownups. Historically, children have all experienced boredom at one point or another. What has changed is how adults perceive and react to the boredom and the inability for some children to manage it. We live in a society focused on productivity and performance, where efficient use of time is valued. Boredom has a bad press. Not knowing what to do translates into a waste of time. When a child says he's bored, we try at all costs to keep him occupied, to find him a jillion interesting activities to do.
Many children, even the much younger ones, have loaded schedules. Between the daycare schedule, the extra-curricular activities in which they are enrolled in, such as swimming, dancing, hockey, music, etc, and the routine at home where everything is planned out, children don't benefit from tons of free time to learn how to organize themselves and decide on what they feel like doing. In which case, it doesn't come as much of a surprise that, when they coincidently have an hour to spare, they are distressed and don't know what to do with themselves.
In daycare, children often have playmates who sometimes turn into models who teach them new activities they would've never thought of on their own. Even if your kid doesn't play with others, nor tries to imitate them, the mere presence of other children provides enough stimulation to encourage him to observe the movement around him.
Learning to play with others is crucial and will bring lifetime benefits. Social skills are required to function and work within a group, not only in school but in a work place also. For example, sharing material, taking turns, taking into account others' opinions, etc. On the other hand, learning to play alone is equally important. It teaches children to decide for themselves. Free play allows your little ones to choose what interest them, therefore developing their independence, another highly prized quality, both at school and at work. Autonomy allows the child to function without constantly needing support from others.
Some children haven't learned to play alone. If this is the case with your kiddo, you can remedy by participating in his activities. It may seem counterintuitive, but if you want your kid to learn to play solo, you'll want to play with him first. Start an activity with him, give some assistance, then step aside. By being in the same room but aside, you can make some comments on how he's doing, "Your tower is really high there!" or "You chose some beautiful colors for your drawing!". By continuing the activity by himself, your child will learn to play and create on his own. He will grow to be more confident in his abilities and develop his autonomy. To provide your child with more motivation, give him the suggestion to draw a picture or create a craft for grandma, his brother, or whoever he knows. Once your child has greater self-confidence, he will be able to play alone in another room. He will no longer feel the need to play before your eyes.
Many researchers consider boredom in children as a springboard to creativity. To fill their loneliness and fight boredom, children will use their own personal resources. Hence, they will listen to their inner world, their desires and tastes. Having nothing to do forces them to develop their imaginary world. Boredom also leads kids to grasp reality differently. They will notice details that they probably wouldn't being kept busy. It's because they're bored that they're observing the water drop travelling down a windowpane or the little ant making its way across the porch. From there grows a story about that water drop or that little ant...
You will benefit from providing free time in your child's schedule. Initially, these moments might seem or be dull, but they will become, overtime, rewarding, spontaneous playtime moments. When your little one is bored, don't rush into occupying him. Encourage him rather to take initiative, "I'm sure you'll find something interesting to do!".