Is ordinary gain on k-1 the same as dividends? bought and sold stock in 2018

No ordinary gain is entered on the return from a K-1 differently than dividends.

Make sure you enter the K-1, and then TurboTax will carry the numbers to the right sections.

so where should stock dividends be entered

If on the K-1 and entered with the K-1 entries you do not need to enter them again.

If you have stock dividends outside the K-1 then entered them as follows:

go to Personal Tab
Wages and Income
I'll chose what I work on
scroll down to Interest and Dividends
go to Dividends and enter them here.