Greetings!
If you have reviewed all your documents and there is no missing document to the best of your knowledge, then your next best course of action is to request a wage and income transcript. The IRS one can be requested at the following site:
https://www.irs.gov/individuals/transcript-types-and-ways-to-order-them
If there is a missing 1099 form, it should come out in the wages and income transcript. Though it only displays federal information, it should generally be enough to use to report missing state wages.
Best regards!
