I paid my taxes when I sent the e-file, however it was rejected. Does this mean I will not be charged on my credit card? And do I need to mail a check instead?

You will have to fix the return and resubmit. What error did you get?

I don't have my PIN number that was mailed to me in December. Now what?

you can check status here <a rel="nofollow" target="_blank" href="https://sa.www4.irs.gov/irfof/lang/en/irfofgetstatus.jsp">https://sa.www4.irs.gov/irfof/lang/en/irfofgetstatus.jsp</a>

That's only for refunds... if you owe, it doesn't work.