When I want to make a Word document that I can edit and make changes to from a pdf, I copy the text in the pdf into a new Word document and paste it as plain text. I then format and set it up using Word controls. I use the original pdf as a visual guide. As you are discovering, documents created in other programs and then converted into Word documents may look right but editing them is a nightmare. There is no one-for-one correspondence of features and methods of formatting and conversion programs do their best.
If you are using a version of Word prior to Word 2007 and want it to be an interactive form, you are pretty much restricted to the Form controls that come with Word. For these to work, the form must be locked or restricted to filling in forms.
Beginning with Word 2007, MS introduced Content Controls, which work without this restriction.