Do i have to file an amendment to include dividend income from HSA investments? I live in CA and didn't know until today that i received DIV of $250 from HSA investments.

Yes, you need to file an amended return for California.

As you now know, California treats HSAs as ordinary investment accounts, so interest, dividends, and capital gains earned by the HSA are subject to California state income tax.

Please see this TurboTax FAQ for how to amend your return with TurboTax - https://ttlc.intuit.com/replies/3288565