Why do i often times not get responses to what should be very simple questions for doctors. was considering perhaps if i started the paid membership then figured healthtap has revealed to me to avoid doing so by leaving questions unanswered?

You are posting your questions on the free portion of the website where the physicians and dentists answer questions as a courtesy, without compensation. There is no guarantee your question will be seen by anyone wishing to answer it, let alone that it would be answered at all. The site does not leave your questions unanswered. It is your prerogative to join the paid service of the site.