The IRS will not tell you if someone used your Social Security number, but if your e-file is being rejected because of a duplicate use of your SSN, you should either seek an IP PIN from the IRS to file your return, or print, sign and mail your return. The IRS will sort out the duplicate use of your Social Security number.
https://www.irs.gov/newsroom/irs-takes-steps-to-help-prevent-refund-delays-by-accepting-duplicate-de...
https://www.irs.gov/identity-theft-fraud-scams/get-an-identity-protection-pin
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
