knitting vertical stripes

have started a scarf with 2 stictches of colour cherryred, then a block of 16 stiches in colour lilac, then ending with 2 stiches of cherryred colour. 
however the beg and end stiches are working up separate from the block, its like i'm knitting 3 individual items on 1 needle. i'm surely doing something not right. can anyone please explain? thanks

Forums: 

When you change your colors are you wrapping the yarns around each other?  If not, this may explain why it appears you are knitting three separate stripes.

thanks KT, no i wasnt wrapping yarn around!!! ooops
in the meantime i started again with horizontal stripes, this time with 10 row of lilac as a main colour and 2 rows of cherry red. so i am ending up with a bit of yarn on the side each time i have a block of lilac. what do i do with the bit of yarn (the bit that ends one row of cherry red till the next one starts 10 rows up). hope i've made myself understood! ;-0 thank you
 

If you were working narrow stripes of 2 rows each, I would suggest that you simply carry the unused yarn up the side of your scarf but with wider stripes broken up with a narrow stripe, I would carry up only the lilac and cut the red when you are finished with it.  Leave long tails -- 4-6 inches so that it will be easier to weave in the ends when you finish. Look up "duplicate stitch" which is a form of embroidery that mimics the lines of your stitches.  When I have to weave in tails for something that is two-sided, like a scarf, I use duplicate stitching to "hide" my tails as I weave them in.