[One neighbor has told me that I need to fix up my appearance, wear some make-up, act like I am alive. ... I don't want to be chastised.]

I can understand that it can feel as if she chastises you even though she probably just means well in her own way.

[ A few months ago, she said that I should have "had at least one child." There's precious little I can do about that now. What could possibly have been her point? Well . . . I guess she was trying to analyze what went wrong in my life. She wasn't being mean . . . just insensitive.]

Yes, definitely insensitive. I wouldn't have been able to deal very well with above comment, but then I have an issue with my childlessness still.
She doesn't seem to understand that being childless is sometimes less a choice than the result of circumstances such as not having met anyone at the time when it was possible to have a child etc.

I would try and distance myself from her, as her insensitive comments obviously upset you, which I can understand. You don't need this in your life right now.

I think you can definitely find other people where you live who appear more supportive, Rose, e.g. by joining an interest group.