1. Preamble

Isolation is the gap between your aspirations for a certain level of social contact and your real level of social contact.
Loneliness is the negative feeling arising from that situation.

2. Feelings

Being alone is not the same as feeling lonely

I personally enjoy being alone, the older I get the more I enjoy my own company

I have no fear of being alone, I love the freedom

But there are many people who feel isolated (limited social contact) and, therefore, lonely.

3. Society

Many societies enjoy the luxury and warmth of having large families where people continuously interact across and within generations.

Love and loyalty is an automatic right for all family members.

Other societies kick their children out of the family nest as soon as they can and farm out the elderly to care homes to die.

In the former, you might suffocate and be weak; in the latter, you might be free and strong but emotionally detached and unsure.

In both, you can feel lonely.