Efile pin why cant turbo tax tell me it

Please clarify if you are referring to the prior-year Self-Select PIN or the 2017 AGI?   If you are in the same account as last year, the information should have transferred in automatically.  No person can provide either of those to you.

The majority of people use the 2017 AGI to verify when efiling.    Why are you unable to get your 2017 AGI?   Was your 2017 return prepared with Online TurboTax?  If so, have you located your 2017 return in that account?    If not, we can help you look for another account.

FAQ:  How do I find last year's AGI?
https://ttlc.intuit.com/community/agi/help/how-do-i-find-last-year-s-agi/00/25947

TIPS:

Use the 2017 AGI from the original 2017 return, not an amended one.

If a joint return, both spouses use the same total 2017 AGI.  Do not divide it.

If you filed real late in the year, such as November 2018 or later, try 0 (zero) for the 2017 AGI.