Currently, the IRS does not allow tax amendments to be e-Filed. You need to mail your amended return to the IRS.
If there is a simple calculation mistake in your previous tax return, then you don’t need to file. The IRS generally corrects the errors while they process your original return. If the IRS wants additional information, they usually send you a mail.
If it has been more than 12 weeks, you can find information about your refund by calling the IRS customer support. However, it takes the IRS 16 weeks to process a return, so you should wait 12 weeks before checking on the status.