Are you talking about visa applications at a US Consulate ... or 'status' applications at the US CIS?
Meeting with an atttorney before filing more papers will be a really, really, smart thing to do.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship. Also, keep in mind that this is an INTERNET BLOG. You should not rely on anything you read here to make decisions which impact on your life. Meet with an attorney, via Skype, or in person, to obtain competent personal and professional guidance.
Normally you can have more than one concurrent application pending at a time. But I agree with me colleagues and it would be good for you to consult with an experienced immigration lawyer to review the facts of your case.