Ruth,
It sounds like the charging port on your Amazon Fire HD is damaged. I would take it to a local tech repair shop in your area to get a quote on the repair. However, I fear that their repair cost might outweigh the price of a new Fire HD, as the current price for a 32GB is $149.99.
If you want to try the repair route, show this article to the technician who might be able to help you:
[guide|87774]
Hope this helps!
-Alex