Too tight cast on

After casting on, the workup row is: slip stich, *k,p,k in same stich, then purl 3 together (in same stich). I cannot seem to purl three together because after the (k,p,k in same stich) the cast on row become too tight!!! Help.

Cast on looser - use a larger needle or 2 of them held together. It seems a little strange that you wouldn’t knit a couple rows before going into the pattern row, but some of them do it that way.

Thank you so much for reply. I am going to knit a least one row, how bad can a scarf look with one knit row at the beginning. I have been knitting for awhile but clearly don’t lack a lot of confidence. It occurred to me to try this but needed a push.

I cast on with a size large as suggested. Works much better this way.