I do chain stitching but sometimes my pieces come apart at the ends and I still have to stitch them again. What am I doing wrong?

I chain stitch all the time, it's a good habit. Use a scrap for beginning your chaining and a scrap for ending your chaining.

From my experience, when chain piecing leave at least 1/8" or smaller end tails between the unit pieces that way when you're done chaining/piecing, clip the threads centered on your units this way the units are uniform & they will not ravel or come undone.

yes, this is the way I was taught also, thanks for posting this for all of us

great tip